Julian: I know he doesn't really get much screen time but I like what little we got from the games and from the anime, also his supports with Rickard are pretty funny. I also like his icon from the nes game. It tells a lot about his character I mean again just look at his supports with Rickard. Not to mention he's pretty much the perfect lover who would travel even to the lair of a dark dragon just to save you even if you only look at him as a friend. Oh and uhm whenever I found a chapter too easy I would just use the warp staff and made him kill the boss/reinforcements while praying to the rng gods
Camus: Yeah he's a boss in fe11 but I love his track and his map, not to mention the build up with Nyna telling you how much she loved him and their story, also fighting the Sable order knowing that if Camus was there it would propably been a much harder battle is pretty cool. Then after defeating him and seeing him return in fe12 and in Echoes/Gaiden feels good and adds alot to his character. I also like the focus on him in the extra chapters and using him in the story of fe12.
The whitewings: I mean yeah some of you might call me a cheater for this one 'cause "Hey that's more than 3 characters" and you are completely right, tho I can't count them as seperate characters since their fun comes from their dynamic. Palla the motherly and carring big sister, Est the young and cheerful yet a bit naive one and Catria the serious yet most emotional of the three. Their supports work well and it's fun to hear them interact. I also liked using the triangle attack on my first playtrough alot. Tho If I had to choose I would propably choose Est. Yeah she joins late and under-leveled but she's just fun and her ending hurt in fe12.
(also sry if I made spelling mistakes I'm making this post late at night and I can barely see what I'm writing lmao)