Nothing is known about Shuichiro's early life, but it is known that he married a young mage in the 0th Magical City of Ishana, and they planned to raise a family together. Shuichiro was a scientist who would often venture abroad to do his studies. He was known across the world as an incredible scientist who often gave lectures at many universities and had won numerous awards for his scientific ventures. He primarily worked in the Seioudai Sampling Laboratory.
At some point, his wife (known only as “Mother”) became pregnant with Konoe A. Mercury (who would later become Nine the Phantom). The pregnancy was dangerous as Konoe had an innate ability to rapidly attract surrounding seithr, which could lead to lethal seithr poisoning for both mother and child. Shuichiro quickly developed an Origin of the Grimoire that absorbed and limited the amount of seithr that Konoe could attract, and somehow turned it into Konoe's left eye while she was still in the womb. Because of this, both mother and child survived. During this time, he was noted to be a loving father and husband, who could focus on both his research and family.
Eventually, the couple became pregnant again, this time with Celica. However, “Mother” died due to complications in childbirth. Her death would lead to Shuichiro's descent into madness and an emotional detachment from the world. His relationship with Konoe worsened, and she began to resent him. Konoe largely blamed him for “Mother”'s death, and believed that Celica was in constant danger due to his erratic behaviours. At some point, he began development on Kushinada's Lynchpin, going fully ahead and planning Celica, with her unique ability to dispel seithr, as the key to activate it, even if it cost her life. During the end of XBLAZE LOST: MEMORIES, he takes time off work to spend time with his daughters, and despite Konoe's best attempts, they would still not see eye-to-eye, even after she had grown up. 
As a researcher and resident of Ishana, he was acquainted with Relius Clover, who was at the time, One of the Ten Sages. Shuichiro was said to have been in awe of his intellect, and was hinted to have even been jealous. At some point before the Dark War began, Shuichiro and Relius came into contact with Yuuki Terumi, who gifted them with the Susano'o Unit in exchange for them working on and developing a Boundary Interface Prime Field Device inside the First District within Japan.
This experiment to create a Prime Field failed fantastically, and the Black Beast was born. It swallowed Relius, destroyed Terumi's body, but avoided killing Shuichiro, who had hoped to activate the now completed Lynchpin in hopes of stopping the Black Beast; without Celica, however, this was in vain. Shuichiro was left to die to seithr poisoning. Celica was compelled to search for him, but Konoe, now Nine of the Ten Sages, didn't care for his apparent death. She took over his laboratory at the family home.
Thanks to a distortion in time and space created by the cauldron that the Black Beast emerged from, however, Shuichiro was still alive 6 years after the emergence of the Beast, even though to him, it had only been a year. Celica, Nine, Bloodedge, and Trinity Glassfille had found him within the bubble of distorted time, but seithr poisoning had thoroughly corroded his mind, and he was essentially a maniac who boasted of the Lynchpin's superiority and that he had finally bested Relius with its creation. He begged Celica to complete his creation, and Nine smashed him into one of the walls of the lab before he finally died. It is unknown if Shuichirou succumbed to the seithr poisoning or if Nine's attack had killed him. Shuichiro's legacy was smeared as he was remembered as the one who began the Dark War as Relius and Terumi disappeared from history.
Shuichiro's lab would later be taken over by Nine as her base of operations where she created the 11th Nox Nyctores - Corpus Sepulcro: Requiem. Nearly 100 years after his death, Nine's views on him would soften as she began to blame the Amaterasu Unit for forcing him and Celica to repeat their fates again and again.
- BlazBlue: Phase 0, Chapter 2 - Destructive Black
- XBLAZE LOST: MEMORIES, Epilogue
- BlazBlue: Phase 0, Chapter 5, Sealed Green