The Conversion Grimoire is a Grimoire held by the Guardian, of which its existence is paired. It takes the form of a liquid within a small glass vial. It was held by the Guardian on the lower levels of the 15th Hierarchical City of Torifune.
The exact properties of the Grimoire are unknown, but Team Remix Heart believed it could convert Mai Natsume's super taste.  Noel Vermillion stole it at some point, and it was used to turn her dreadful cooking into something delicious.  When the Guardian was presumably killed by Relius Clover, the Grimoire disappeared as well despite being in a safe watched over by Cypher Albar. 
- BlazBlue: Remix Heart, Chapter 06
- BlazBlue: Remix Heart, Chapter 10
- BlazBlue: Remix Heart, Chapter 17