Raabe is a member of the Mitsurugi Agency and Independent Thought Unit that has a personality based on Kagami Hajou. It is unknown if Raabe was created aboard the Dimensional Boundary Submersible Warship Fugaku or in the Possibility that Kagami originated from. Raabe Dives with Ciel Sulfur into the Phantom Fields to free the Observer trapped within them.
Both Raabe and Ciel dived into a Phantom Field which was set within the Magister's City of Ishana prior to the Dark War. Unfortunately, Raabe was not working properly during this Dive, being unable to speak and being barely capable of its usual powers. Raabe stuck by Ciel's side throughout the Field, being able to communicate with her. Eventually, the two were found by Another Dark Mai, who attacked Ciel. The battle was interrupted by Rei, who had accidentally wandered between their fight. Rei subconsciously used Phenomenon Intervention, giving Ciel time to take Raabe and Rei away from Dark Mai and escape.
Rei introduced themselves to Ciel and Raabe, and the trio were soon joined by Kazuma Kval, a student at the school who had been with Rei before they met with Ciel and Raabe. Monsters soon surrounded the group but they were soundly defeated, although Raabe was clearly annoyed by Rei's lack of ability with either magic or sorcery. Dark Mai soon found the group, jumping down next to them and threatening to kill them. Raabe then used Phenomenon Intervention to place the group onto the other side of the island, far away from Dark Mai. Doing so caused Raabe to deactivate until it was reactivated by Ciel repeatedly hitting it on the side, something that only made Raabe just more angry. Ciel then introduced herself and Raabe to Kazuma and Rei, but under Raabe's nudging, only slight details were omitted. The group came to realize that Ishana was in an unusual state as there were no other people in the island. In order to solve the mystery, they decided to venture deeper towards the center of the island and try and locate the cauldron. More monsters then attacked the group, but they were defeated.
Due to the swarm of monsters that the group kept coming into contact with, since Ciel, Raabe, and Rei were Contaminants, the group agreed that they would head north-east towards the island port where communication devices lay. There was nothing they could use, and the silence was cut through by a piercing scream coming inland. Raabe watched as the various waves of monsters were killed and the source of the scream was saved: Trinity Glassfille. Trinity told the group that Ishana was seemingly in another dimension as part of a secondary defence system that was activated. In order to find a solution, Trinity advised that they head for the Great Library.
To avoid the monsters and Dark Mai, the group travelled through the sewer system to reach their destination. Ciel tried to tell Trinity and Kazuma that she was there to save them, but was about to reveal details that Raabe deemed unnecessary. Raabe hit her and signalled that the information she was about to reveal regarding the Fugaku was not needed. Despite their best efforts to avoid monsters, more managed to find them. After the battle, the group exited the sewers and found themselves in a park that was a short distance away from the library. Raabe picked up on Trinity passively mentioning that she had been here earlier, but had been transported to a forest after being unconscious for a short period.
When the group finally entered the Great Library, Trinity made them aware that they would have to fight a security system in order to proceed to the usually forbidden sections. After the system was beaten, she told Ciel and Raabe that she felt uncomfortable allowing them within this section due to the fact that they are outsiders to Ishana. Rei and Kazuma managed to convince her to let them in. Raabe helped the group comb through the various books to find information that could help them, eventually finding one on the urban planning of Ishana. Handing it to Ciel, she was able to formulate a plan with the others: find the cauldron and stop it in order to free Ishana from the dimension it was trapped within. To find the cauldron, they headed towards the most sacred of places within Ishana - the Ishana Cathedral. On their way there, Ciel confessed to the group that she was going to destroy the cauldron, casting suspicion onto her and Raabe from Kazuma and Trinity, but Rei reaffirmed their trust in them, causing the two mages to realize that they had no reason to doubt the two Mitsurugi Agency members.
Raabe pointed out to Ciel that the Ishana they were in was created by Trinity to fulfil her wishes, and that she was the Observer within the Phantom Field. Armed with this new information, both Ciel and Kazuma confronted Trinity and told her that she was the Observer. More monsters came, seemingly guarding the cauldron underneath Ishana. When the group finally managed to find the cauldron, they saw it was guarded by Another Dark Mai, who challenged them to battle. After the fight, Dark Mai escaped through the cauldron and Trinity, unable to accept that she was the Observer and unable to accept that her desires might escape her, turned against the group. Trinity was defeated. Ciel used the BlazBlue Alternative after Rei Observed it, and the cauldron was destroyed. The Phantom Field began to reform into a Possibility. Ciel, Raabe, and Rei were then taken aboard the Fugaku where Raabe was able to receive repairs.
Back aboard the Fugaku, Raabe was fixed. Not soon afterwards, it was deployed with Ciel and Rei to infiltrate another Phantom Field. It introduced itself to Rei and explained that it was based on Kagami's personality, but they were not the same people with the same thoughts. Both Raabe and Ciel then began to talk about the methods they could employ to find the Observer within this Field. They recongized that the Observer will have a Drive and will also instinctively avoid the cauldron within the Field. Ciel went to conduct some reconnaissance and during that time, Raabe told Rei that the highest priority is their survival. Ciel shortly arrived afterwards, telling them that she had found monsters that were enhanced by seithr, but also that there were residents within the Phantom Field. Raabe watched as Ciel and Rei defeated the monsters.
When they approached the village, the villagers were noticeably injured. Despite their hesitation, Raabe proceeded to heal their wounds but they were soon surrounded by the Novus Orbis Librarium, who mistook Raabe, Rei, and Ciel as members of a local resistance. The group fought against the NOL, winning. This victory was short lived as a version of Tsubaki Yayoi appeared, rallying the soldiers together and bringing reinforcements. The trio were unable to resist the overwhelming numbers in front of them and were arrested.  The trio were taken to a cell in the 17th Hierarchical City of Yamatsumi, where Tsubaki began to interrogate them. However, she learned that the three of them did not know about the NOL, so she explained the organization to them as well as the concept of a Hierarchical City. When Ciel went to explain about the Mitsurugi Agency and Phantom Fields, Raabe stopped her and imitated her to try and distract Tsubaki from what she was just told. Eventually Tsubaki left, leaving Raabe to chastise both Ciel and Rei about telling Phantom Field residents too much information.
The group decided to aid the resistance in order to learn more about the Phantom Field, as this would allow them to discern the identity of the Observer. Raabe and Ciel noticed that Tsubaki has a Drive, but were not sure if she was the Observer. Their conversation was interrupted by a woman in another cell, who picked up on that the trio were from another world. An explosion then rang out through the NOL branch as members of the resistance broke through, led by Kuon Glamred Stroheim. They rescued the woman in the other cell, the leader of the resistance, and she introduced herself to the group as Bullet – together, the group began to escape. 
The NOL gave chase. Rei, Ciel, Raabe, Bullet, and Kuon stuck together to distract the NOL from other resistance members who were freed. They fought against a security golem, besting it.  Once the group had escaped Yamatusmi, Bullet offered them the chance to join her and the resistance. They turned her down, and instead she told them of a village where they could stay for the night. Kuon guided them there and confided that she was a Contaminant; both Raabe and Ciel told her the situation and how she could return to her own world. Eventually, the group arrived at the village and were able to rest. The following morning, they listened to the villagers impressions of both the resistance and NOL before leaving for another village.  The next village they arrived to was under attack by monsters. Bullet was also there, fighting against them, so the group came to her aid. Once the battle had ended, Bullet joined the group to escort them to the next village. Both Ciel and Raabe had noticed that Bullet was a Drive user, so kept their eyes on her in case she was the Observer.
The path to the next village was crawling with monsters; the group destroyed them in order to proceed. In the village, it was clear that everyone there adored Bullet. Raabe took notice of this. Bullet told the group that she would help them as much as she possibly could. Raabe, Kuon, Rei, and Ciel took on a mission from Bullet: infiltrate Yamatsumi to locate a resistance member trapped within the city. They agreed and were able to access the city with little difficulty. They soon found the agent and agreed to escort him out of the city at night through the sewer system. Raabe stayed behind to monitor him while the others left to gather information. When the night approached, the group left for the sewers, but were caught by patrolling guards. With no other choice ahead, the group fought their way through.
The sewers were filled with demons, which the group were forced to fight through. After fighting through hoards of monsters, Raabe and Kuon discussed how unusual the NOL was acting. Despite being on high alert for resistance members, the entrance into Yamatsumi had been easy and the guards did not care much for Kuon's explosive fight earlier that day. Their conversation was interrupted by Ripper, who leapt into the fray and attacked both Kuon and the agent, leaving deep slashes on them both. Raabe was stunned at being unable to track Ripper before his arrival. Ciel took over to fight against Ripper but was losing until Bullet burst through the sewer system with reinforcements from the resistance; Ripper fled in response.
Bullet escorted the group back to a village where they could recover. Ciel, Rei, and Raabe decided that they would be going to investigate the NOL within Yamatsumi. Kuon stopped them, telling them that she would be joining as she felt responsible for Ripper since they were from the same Possibility. They made their way to the higher levels of Yamatsumi to get a better understanding of the city, but they were almost immediately spotted by Tsubaki and the NOL guards surrounding her. The guards attacked the group, but Tsubaki interrupted them, dismissing the guards. Raabe offered to give her information about the resistance so long as they could talk in private. Tsubaki agreed.< ref>BlazBlue Alternative: Dark War, Chapter 1, 7 – 2</ref> They moved to a more private area, where Tsubaki asked them to be mediators between herself and the resistance. Jin Kisaragi would be arriving in Yamatsumi soon with reinforcements to continue building and managing the city, and they were going to destroy the resistance as well. The group agreed to help as mediators to avoid bloodshed. 
On their way back to the village from Yamatsumi, the group was attacked by Ripper. He declined to answer any questions on who he was working for and attacked. Tsubaki interrupted the fight, causing him to flee. She handed them a communicator so they could contact her about the negotiations easier, but they let her know that Ripper was likely acting under NOL orders, meaning that any treaty would be more difficult to negotiate. Regardless, they still agreed to act as mediators. They continued their way back to the village but found Bullet and other resistance members in the middle of a raid. They learned she was going to steal a mechanical shaft that was essential to the development of Yamatsumi. They extended the offer for negotiations that Tsubaki wanted, but Bullet declined, telling them that she would never join the NOL nor would she allow them to continue to do as they please. To prevent them from leaking the raid to Tsubaki, Bullet ordered that the resistance members apprehend the group, but they were powerless to do so.
Ciel called Tsubaki and alerted her to the raid. Tsubaki relayed that those parts had already arrived. and that Bullet had likely been given false information. The raid would instead be on a civilian ship which could lead to fatal casualties. Tsubaki reunited with Rei, Raabe, Ciel, and Kuon and also made her aware that Bullet had declined their peace offering. Before they could act to stop her, they were interrupted by Hibiki Kohaku. He told the group they were under arrest as they had broken from the jail they were confined to earlier. After a fight, Tsubaki ordered the group to leave and stop the resistance while she held off Hibiki.  They caught up to Bullet and helped her escape from the NOL after telling her and the resistance that they had been set up. When they returned to the village, the group found it was destroyed with scores of dead bodies. Ripper had destroyed it and killed as many people as he took pleasure in doing so. Bullet swore revenge on the NOL, knowing that this order must have come from Hibiki Kohaku. She rallied everyone together and ordered that they would destroy the mechanical shaft. Kuon, Ciel, Raabe, and Rei pleaded with her to reconsider, but these pleas fell on deaf ears. The group decided that they needed to see Tsubaki.
The following morning, Kuon, Raabe, Rei, and Ciel were surrounded by the resistance, weapons raised. The group struggled, hoping to break free, but this ended when Bullet arrived and took Rei hostage. Ciel was held back by Raabe, as she could not guarantee Rei's safety by fighting back against Bullet. Raabe had noticed that the world fought back against the group whenever they tried to bring peace, and it noted that perhaps it was the Observer's subconscious wish to be embroiled in conflict. Bullet and other members of the resistance left to execute their plan, allowing the group to break free and rescue Rei.
As the group made their way towards Yamatsumi, Raabe called Tsubaki and made her aware of what Bullet was aiming to do, and also told her about the massacre that Ripper had enacted upon the village. Tsubaki told them that the shaft the resistance was targeting was essential to Yamatsumi's infrastructure. Without it, the city would collapse. They were able to reunite with her and a group of NOL soldiers loyal to her. The group ventured deeper into the NOL branch, finding no guards protecting the perimeter. Tsubaki noted that the soldiers were likely being led by Hibiki and battling the resistance on a higher level. They accidentally activated a security golem but were able to destroy it before proceeding.  Ripper then appeared, confessing to the slaughter of the villagers. The group battled against him, managing to defeat him and forcing his retreat. Ciel and Raabe made the decision that they would have to push forward to find Hibiki and Bullet before it was too late.
The group found Bullet and Hibiki locked in battle and surrounded by unconscious NOL soldiers and resistance members. Tsubaki interrupted the fight and tried to persuade Bullet to make peace. Her words got through to the resistance, but Bullet remained steadfast in her position of violence. Time rewound to moments before the resistance accepted her offer, something which Rei, Raabe, and Ciel noticed. Instead of accepting her offer, they turned against Tsubaki and the group prepared for battle.  When they finally found them, the two were locked in battle while soldiers from the NOL and the resistance lay nearby. Tsubaki pleaded with them both, begging the violence to stop with a passionate speech that resonated with the nearby soldiers. They pleaded with Bullet to stop the violence but she refused and the Phantom Field began to rewind back to before the soldiers agreed with Tsubaki. Now they turned against her; Kuon, Ciel, Rei, and Raabe defeated these soldiers.
Reinforcements came to back up Bullet and it was then that Ciel and Raabe knew that Bullet was the Observer of the Phantom Field. They were able to conclude that all she wanted to do was to fight forever, and that any attempts to stop it would always be prevented. Peace or victory were never options, only violence. Ciel was then able to confirm the presence of a cauldron and explained that they could destroy it to free the field. Hibiki sided with the group, but Bullet then began to attack, not letting them take away the only thing she had ever known – violence. Monsters flooded in, generated by the Phantom Field to exterminate the group.  The Phantom Field then began to operate to continue the battle forever, something that Bullet could not even control. Hibiki, under the Observation of the Field, changed sides to fight alongside Bullet, and the two attacked with combined forces from the NOL and the resistance.
Bullet's Observation then focused on Tsubaki as it tried to make her hostile towards the group. Tsubaki tried fighting back, but it was a losing battle until the arrival of Jin Kisaragi. He demanded that Tsubaki move to the backline while he stood with Ciel, Rei, Raabe, and Kuon to fight against Bullet.  The group was able to defeat Bullet, who accepted the outcome. Jin stayed behind to look after Hibiki as everyone else went to the cauldron. Raabe reassured Kuon that she would return to her own world after the Phantom Field reformed. Ciel destroyed the cauldron, allowing her, Raabe, and Rei to return to the Fugaku. Back on board, Kagami congratulated them on the job.
- BlazBlue Alternative: Dark War, Prologue, 1
- BlazBlue Alternative: Dark War, Prologue, 2
- BlazBlue Alternative: Dark War, Prologue, 3 - 1
- BlazBlue Alternative: Dark War, Prologue, 3 - 2
- BlazBlue Alternative: Dark War, Prologue, 3 - 4
- BlazBlue Alternative: Dark War, Prologue, 4 - 1
- BlazBlue Alternative: Dark War, Prologue, 4 - 3
- BlazBlue Alternative: Dark War, Prologue 5 - 2
- BlazBlue Alternative: Dark War, Prologue 5 - 3
- BlazBlue Alternative: Dark War, Prologue 6 - 1
- BlazBlue Alternative: Dark War, Prologue 6 - 2
- BlazBlue Alternative: Dark War, Prologue 7 - 1
- BlazBlue Alternative: Dark War, Prologue 7 - 2
- BlazBlue Alternative: Dark War, Prologue 7 - 3
- BlazBlue Alternative: Dark War, Chapter 1, 1 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 1 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 1 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 2 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 2 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 2 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 2 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 3 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 3 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 3 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 3 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 4 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 4 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 4 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 5 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 6 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 6 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 6 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 7 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 7 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 7 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 8 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 8 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 8 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 9 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 9 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 9 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 9 – 4
- BlazBlue Alternative: Dark War, Chapter 1, 11 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 11 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 11 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 11 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 12 – 1
- BlazBlue Alternative: Dark War, Chapter 1, 12 – 2
- BlazBlue Alternative: Dark War, Chapter 1, 12 – 3
- BlazBlue Alternative: Dark War, Chapter 1, 12 – 4