Tibarn (Fire Emblem Series) vs Fou-lu (Breath of Fire IV)
Physical spoiler.
(Belated response to the Week 2 comments from Random & Jo'ou, but yes, Persona bosses are traditionally massively overrated in the DL thanks to incredibly badass buffs & debuffs that come down on turn 1. I'm just not inclined to respect Tibarn's damage as THAT huge. You'll note I did vote for Tibarn last week anyway!)
Heavy
Nera Briscolleti (Dragon Quest V: Hand of the Heavenly Bride) vs Corrin (Fire Emblem Fates)
Levin Sword strats mean Kafrizzle is out. That said, Corrin doesn't OHKO, so Nera can serve up 2x Thwack attempts against Corrin's averagish Res. Kneejerking that status as turn 2 or so for the moment, so.
Tana (Fire Emblem: Sacred Stones) vs Yuffie Kisaragi (Final Fantasy VII)
Doubling interps ahoy! Yuffie 2HKOs so Tana absolutely has to double herself and kill on turn 1 off 2x Javelin counters + 2x Silver Lance. 28 Spd / 27 Attack Spd to a 20.5 average will do that to 107% avg. speed Yuffie to me, though, so sure, Tana, but she does die horribly if you don't see her as doubling. (You could also let Yuffie hit a weakness here, but eh, if FE Heroes is any indication, daggers / ranged ninja stuff don't hit weakness on fliers) (EDIT: Right, evasion too, that could also tip it to Tana even if she didn't double.)
Middle
Freya Crescent (Final Fantasy IX) vs Elliot Craig (The Legend of Heroes: Trails of Cold Steel)
Berserk is one of the few statuses Trails doesn't have and thus doesn't block.
Setsuna (I Am Setsuna) vs Lucas (Mother 3)
Uhh.. can anyone vote this? They're both slugs, dunno whose speed to disrespect more, double turns seem like they help for breaking through this healing stall-off since both pack cheap healing that would outpace expensive offense like PK Love. As best I can tell strictly off the stat topic, Lucas wants to fish for a really good disabling status off his status move, or possibly buff his physical and try to pressure Setsuna more. Setsuna wants to wait for some powerful Singularity or else heal into a deadly Holy Light... but that's problematic since Lucas reflects Lightning, and Lightning & Light elemental are the same thing in IAS, so arguably Setsuna is just stuck with Chakram beatdown? idk
Light
Otome Yanagiya (Shin Megami Tensei: Devil Survivor 2) vs Cyrus Albright (Octopath Traveler)
Faster, 2HKOs first through Cyrus's regen. Cyrus might possibly 2HKO back with an Elemental Heavy Armor setup but you still need to see him as faster.