Godlike: (totally uninteresting)
Myria(BoFs) vs Loki(VP)
Heavy:
Songi(LoL) vs Hrist(VP2) - Gamebest Avd for what it's worth, pretty high defenses. That DAMN DARK WEAKNESS. Her HP isn't THAT great, but not so bad coupled with her defence that she'd go down in one hit. Meanwhile she 2HKOs, probably. Yeah, unless someone does the maths...
Middle:
Venusaur(Pokemon) vs L'Arachel(FE8) - Dodge, zap, dodge, zap.
White Wizard(FF1) vs Blastoise(Pokemon) - As much as Venusaur VS Blastoise would amuse me...
Light:
Lucia(L2:EB) vs Yam Koo(S2) - Lemina-esque stats with Jean-level defence, you say? Yam Koo has more speed and 3HKO damage against average... maybe 2HKOs Lucia. He hits her. She increases her defence. He hits her again and fails to kill, Lucia heals. He hits, maybe doubles, still fails to kill, Lucia heals again. (at this point she trumps Leo's defence)
OK, let's math. Yam Koo does 0.36 HP against average. Lucia has 0.79 HP. So he barely misses the 2HKO. He hits her, Lucia casts Magic Barrier and buffs her defence to around 270. Puts her at 1.23 average defence, with the note that defence in Lunar isn't that significant. Assuming 2 def = -1 damage as Lunar 1 has... this means 24 less damage than average... means 0.96 damage received. This nerves Yam Koo to 0.3456 damage, let's say 0.35 for ease. ... lol.
No matter what, he will 3HKO her because the difference is really negligible between Lucia's actual defence, and her buffed defence. She'll probably heal instead, then, which she can do easily. Assuming Lucia heals every round, and Yam Koo only doubles her after let's say four rounds...
First round, Yam Koo attacks. Lucia retaliates. Yam Koo attacks, Lucia heals. Yam Koo attacks, Lucia heals. Yam Koo doubles, Lucia heals. Attack, heal, attack, heal. Attack, Lucia retaliates, attack, Lucia heals. Double. Repeat ad nauseum.
Her heal recovers 0.55 HP, so she can easily outheal his damage. His damage is incorporating his average crit chance which is once every three hits, so potentially Lucia has even MORE leeway considering he doesn't crit on every hit and thusly does less damage per hit.
Yeah, going to say Lucia bags this one. Yam Koo double-critting on a double just seems unlikely to me.