Mouse in Fandom's Hell

Callisto is shown as the most supportive Nursefather, letting tiny Ryoshu to go to school. But then when she gets bullied, Matthias being a Big Bro, goes out of his way for vengeance

And Callisto is not happy about this, calling Matthias the 'senseless/barbaric' one

This shows Callisto in a 'positive' light until Ryoshu mentions that the next day he presented a 'snowman' made out of the murdered classmates' head. It further reinforces that Callisto is just as bad at considering Ryoshu's feelings in the matter when he shows his art in front of Araya, obviously terrified by it.

Matthias and Callisto are both the type of person who only care about their ideologies and themselves, their 'love' being conditional, something that only comes when it benefits them.

Kira had a hard time spending time with Matthias bcuz all he cared about was his own favourite retro toys and stuffs. For someone who's in a gang whos motto is 'they never forget', he seems not to care about anything that doesn't interest him. (Matthias!Outis buying the wrong magazines in Kira!Ishmael ID story)

Callisto failed to stick to his valuables as an artist: "art is subjective, and shouldn't be forced onto others". Yet, he is enforcing his art onto others to prove his art still stands even after he made his magnum opus 'Tibia'. He's a dilemma of 'does it worth continue to create when you've already hit the highest point in your career?'. He's no longer creating art for himself but chasing after validation, and Hohenheim clocks him fast that his art has 'no soul'.

Edit: HongLu ID mentions his view for Corpotism is to unite. He's clearly having a really bad job with it lol

Tldr.: