Maribelle. She has a good sense of humor and is somewhat of an oddball. The conversation she had about "slang" with my MU goes in my top 10 for most entertaining supports. Pretty much each one of her supports (to units worth supporting) tend to have something funny OR sweet/dramatic in them.
Second is Gaius. Smartass who loves sweets. His recruitment shtick had me hooked. His supports are pretty awesome too. He's an "honorable thief" with great dialogue that doesn't make him seem like bleeding heart dandy like most "honorable thieves". Also, green eyes + red hair + naice voice.
Third is Yarne. Cowardly buff bunny boy. His mother was kind of boring (reminded me of Fran from FE12, but not as cool). His lines are pretty entertaining. I particularly love his confession scene. . . That's the best proposal my female MU has ever received. "Yay Yarne, you did it!" "NO ANASTASIA. WE'RE GOING TO DO IT. RIGHT NOW"