ロットカーマイン

Arakune when he was still a human and a researcher at Sector Seven. His dialogue between many characters, as well as his Arcade Mode ending, suggest that it was the power and knowledge he obtained from the Boundary that gradually turned him into what he is, and notably he does not seem to have noticed that he is changed, and to him, his bizarre speech is completely normal. He seems to not understand why others cannot understand him, creating a crude mask for himself thinking it would allow others to understand what he is saying.

As he wanted to observe the Abyss of the Azure, he followed a theory which brought him closest to the truth that he was seeking. That is why he attempted to refine himself into the Azure Grimoire. It is shown that he fused himself with some seithr from the Boundary, which then turned his mind upside down and started going insane, not to mention forgetting the people close to him. Because of this, he also started creating reports only about the Azure - which were all rejected by Kokonoe.