About your servant Goetia au post, I know there's a word for that, but I forgot what it was but it was along the line of exclusive rivals trope I think? Not yandere I think. I know there's a trope where one character sees the other as a rival but the other doesn't (maybe someone they don't even notice or someone they see as a friend instead) I just really can't remember the name for that one or the other(mentioned it because guda befriends all their servants). I still love the concept though I'm still trying to remember what that type of trope is actually called.
anon, i think i'm picking up what youre putting down so i took it to tv tropes
for exclusive rivals, i raise The Only One Allowed To Defeat You
"One person or group considers another person or group as their rival, and will not allow anyone else to be the one to defeat them. This can sometimes lead to them helping their rival against other enemies, justifying it with a lame excuse, to make sure that they survive until the final battle between the rivals."
which is the type of relationship i was going for!
but as for the "lopsided rivalry" i would say Unknown Rival, the main article description doesn't really put it in the right words. i recommend looking at some of the examples liiiiike:
Cecil and his brother-in-law Steve Carlsburg from Welcome to Night Vale: steve also being a super upbeat character that does genuinely see cecil as family. cecil finds every chance to seethe on air about the horrible steeeeeve carlsburrrrg....
or the El-Hazard: The Magnificent World OVA: "Makoto is largely unaware of Katsuhiko Jinnai's hatred for him; in fact he considers Jinnai a friend."
annnd finally from My Hero Academia: "Bakugo also ... constantly sees Midoriya as some kind of rival, but Midoriya never notices and treats him as a friend."