Vitali (Soul Nomad & The World Eaters) vs Lucius (Fire Emblem: The Blazing Sword) - Vitali fucking sucks. He's getting countered by Lucius every single time he tries to attack with his Estella-tastic physical, is slower and Lucius might even double with a Lightning tome (although I doubt it). The special attack gets mocked by Lucius' MDef to boot.
But... this is exactly the kind of fight where Vitali can actually -do- something?
Vitali has awesome RES, Lucius isn't OHKOing. And SN's rock-paper-scissors form of strengths and weaknesses has it so that Vitali does much more damage against mage-type enemies. (And if you see Lucius as more of a cleric-type, Vitali's still strong against those, too).
He spends the first 2 rounds -not- attacking, so therefore, he's -not- provoking counters. In fact, he's buffing or healing.
By the third turn, Vitali's buffed, dealing roughly-average damage against Lucius' weaker defensive stat, and able to simultaneously full-heal and further buff himself while attacking for 3 turns (cancelling out any counter-damage).
I personally think those three turns are enough to take out someone frail like Lucius, but your mileage may vary. After those three turns, he can still deal damage, and his buffs are still up, but he's out of healing and his buffs run out in 3 more turns... not to mention his stamina will be lowered at that point and his stats will start dropping, so if he doesn't kill in those 6 turns, he's definitely burned.
Still, this is definitely one of Vitali's better match-ups. He -does- suck, but he's at least got a shot here.