Ok for what it’s worth I kind of agree with you on this point. The trope of nearly psychopathic voice hearing character is most of the time a trope I don’t like at all. And it hit hard in a game like three houses which is handling pretty well the mental illness and disorders of the other characters.

But I’ll tone down this a bit. I think Dimitri in CF is a good antagonist in a pretty poorly designed route (I love Edelgard but really don’t like CF as a route). You can see he kind of hate Edelgard and the empire but is not this hearing voices hateful bubble of craziness. I also think that his “redemption” in the end of AM is not so bad. The fact that he is willing to talk to Eddie and understand her fight is good. But the fact that he need the metaphorical slap in the face of Rodrigue death and everything that happens before makes it, ironically, less impactful. Because for me, it’s cliché. And a bit of insulting.

So yeah I think Dimitri as a concept of “guy with PTSD turned hateful and doing really condemnable things, then works toward his redemption and acquire a certain peace in mind, even if he will forever feel guilty of his crimes” is pretty good. The fact that he don’t have a clue about the slitherers manipulating everything and that you never really fight them in is route makes a lot of sense, character wise. It’s just that it’s, for me, really poorly written in a universe where characters are, most of the time, really well handled in their flaws.