Godlike
Reicher (Mana Khemia 2: Fall of Alchemy) vs Heat (Digital Devil Saga 2): Remote Blade OHKOs a tentacle and isn't subject to stat downs, meanwhile Reicher has decent MT on his own turns as well. Just a bad matchup for Heat.
Empyrea (Dragon Quest VIII: Journey of the Cursed King) vs Black Mage (Bravely Default): Faster, ORKO.
Yuri Hyuga (Shadow Hearts Series) vs Jezuit (Breath of Fire: Dragon Quarter): Faster, ORKO. If Yuri could tank this opening hit he would need to instant lap with For Everyone and heal and then he might win since he does have MT, but not certain. But yeah, the ORKO is pretty clean, even being relatively harsh to Jezuit (i.e. scaling him against 25% resistance and forcing him to use some AP on movement).
Ryu (Breath of Fire IV) vs Airy (Bravely Default): Well if Airy goes first she wins. If Ryu goes first... things get... interesting.
First of all, Ryu equips a Flame Sword, since it has the same weight as Firangi, -23 power (-460 damage) but does 1.5x here. Ryu will transform into Kaiser, Airy will use Acedia (and/or Default with the intention of using Acedia next turn). Acedia Zeta Flare does around 52-52% to Kaiser. Kaiser will first use Kaiserbreath. Then he gets 1-2 turns (depending on if you see him as at least 3% faster than Airy at base). He can Sanctuary to remove Acedia and yeah he probably should since it means Airy spends 2 BP killing him (Slaughter will work at this point, and/or Acedia + Zeta Flare again). If he has a free turn, he uses a Flame Sword physical. Airy uses Slaughter because whatever, Kaiser is a jerk. Ryu gets two turns, transforms into Weyr and uses Gigaflame. And... yeah the situation repeats, Airy can't OHKO with anything here and needs 3 BP minimum to win, so Ryu gets a chance to use some more fire, 2-3 more turns more likely. And this continues on with other forms. Unless I'm missing something, Ryu should win if he's is faster.
That's a big if. Abstain for now.
Heavy
Nina (Breath of Fire IV) vs Amon (Lufia 2: Rise of the Sinistrals): Huh I overrated Amon's magic damage in my head, maybe him vs. Ephraim was closer than I thought. Oh well. However, Confuse can heal-lock here, and Nina isn't that much faster. Confuse immunity gets her OHKOed. I think her main hope is that her evade works against confuse, that would give her extra turns to work with... but it's probably not enough.
Mei-ling (SaGa Frontier) vs Cresselia (Pokémon): Uhh... buffed Megawindblast 4HKOs, buffed Boundshot and Trickshot 3HKO. Cres' only buff is Double Team but since that only works on Trick Shot it's probably not worth a slot. Cres heals 5 times for 50%. On the other side of things, Psychic 3HKOs and again Mei-ling heals for around 50%... but far more times. Largely symmetric resource war outside of the greatly different amounts of healing I think. Psychic could proc SDef Down but that doesn't actually matter much, and it runs out of PP around the time it does, leaving Cres with less damage.
Lyndis (Fire Emblem: The Blazing Sword) vs Basilio (Fire Emblem: Awakening): Lyn uses a bow, outslugs, the end? She 2RKOs with that so triggers at most one counter and Basilio isn't going first with melee so the absolute worst case scenario is one Basilio turn of his own, that only kills her if all three hits (Brave Axe + Silver Bow counter) hit and they won't.
Jowy Atreides (Suikoden II) vs Rydia (Final Fantasy IV): Faster. Not much to say here, no damage average is saving Rydia.
Middle
Lightning Farron (Final Fantasy XIII) vs Karsh (Chrono Cross): Karsh does above average damage without even using a tech (dat str), which beats out Lightning's healing, and then the killer turn comes.
Izlude Tingel (Final Fantasy Tactics) vs Gallows Carradine (Wild ARMs 3): 2HKOs/heal-locks. Gallows can fire one summon off and that's it? Well, he may be able to heal once or twice first, building some FP. Actually it's not crazy that this might be enough to kill, although Mind Break would ruin that real bad... and Magic Break ruins it worse if you see that working. Eh, I've got enough Izlude HP respect for this.
Raven (Fire Emblem: The Blazing Sword) vs Chrom (Fire Emblem: Awakening): Raven is +4.9 AS, Chrom is +1.6. So Raven doesn't double, which means Exalted Falchion's healing is far too potent. Chrom kills after Raven's second attack. Hand Axes struggle to hit and only break the regen on a crit, so that has to be a losing prospect.
Ennarcia Dysler (Mana Khemia 2: Fall of Alchemy) vs Lilly Pendragon (Suikoden III): 2HKOs.
Light
Alenia (Suikoden V) vs Irvine Kinneas (Final Fantasy VIII): "Not Alenia" should be good enough here, dunno if he needs a limit but he can probably get one since Alenia is slow and IIRC has a reasonably high 3HKO, a bad place to be.
Tia (Lufia 2: Rise of the Sinistrals) vs Leon D.S. Gehste (Star Ocean: The Second Story): Surely.
Randi (Secret of Mana) vs Marivel Armitage (Wild ARMs 2): Faster, so sleep is junk and ID is turn 3. The only question is whether Randi 2HKOs and it's a moot one.