Kirbin vs Corvette
Major vs Sonic

R1
- Sonic is Mach and has super piercing. He can grab his gear and attack Major in 0.2 seconds. Major takes 0.5-1 second to cloak
- Major's guns hit big and she has effectively perfect aim, even against supersonic objects. Sonic is a talker

R2
- Sonic only talks to weak people, Major doesn't necessarily cloak. Bullet timing is in a simulation
- Sonic is a jobber and his piercing sucks

I buy that Sonic is stupid more than I buy Major is stupid. Furthermore, I think the "in character" argument for Sonic being talkative works against him here. Sonic talks to people he thinks he can easily beat, and the whole argument here is that Sonic blitzes and one-shots Major before she blinks. Therefore, Sonic talks.

I am split on Sonic's piercing. I think the kunai is clearly bad. I buy that the sword is good. Even if the suit is just "metal", that's still a relatively good piercing feat. And even if it doesn't one-shot Major, that whole line of reasoning is kind of irrelevant. If Major is in sword range she dies anyways, even if the sword is chip damage. "Major can get away once in melee" was never an argument in here.

I think the fight is going to just come down to whether or not Sonic is facing Major's direction when Major shoots him. Major will definitely cloak, and she can definitely shoot Sonic. Sonic isn't going to run immediately to the weapons cache in 0.2 seconds even if he does know where it is. But if he can see the gun fire then he can just dodge and run towards the muzzle flash location.

I'm giving this a tie right now.
Nuke vs Shishio

R1
- Shishio can bullet time, cuts though stone and can take stone-cratering punches. Also makes fire. He dodges Nuke's aim and eats him in melee
- Nuke is the tier setter. Zero-Shiki isn't bullet speed and is explicitly subsonic. Nuke tanks Shishio and shoots him massively with ease

R2
- Shishio hits harder than Nuke, Zero-Shiki antifeats aren't real, and he cuts good via not trying very hard
- Shishio's scaling is mega fake and Saito is slow. Nuke shoots him and no-sells

Okay, well, Shishio definitely isn't fast. I think that was proven more than thoroughly. So I'm going to ignore "dodges the bullets" as an option here. I think Shishio is faster than Nuke in melee, but he isn't bullet timing, essentially.

I'm really iffy on Shishio being able to cut Nuke. Shishio's feat sucking but only sucking because he was barely touching the rock is definitely real, but I'm not sure if that overcomes "effortlessly" slicing through steel. I'm going to say that Shishio can injure Nuke with a strike, but it would take successive hacking to actually kill him. Much like the Headsman scan itself, essentially.

This leaves Shishio in a position where he must cross the arena distance without getting hit (lucky!) and then hits Nuke like 10 times in melee without getting hit himself (less lucky). Considering that Shishio definitely isn't fast, and I'm already being generous with how well he can cut (if he cuts like Saito does, the headband scan just means Nuke no-sells). Nuke wins by shooting hugely with his gun.
Sabretooth vs Luffy

R1
- Big rock throw good, smash. Speed is comic_scaling.png. Sabretooth ambushes Luffy with his good senses and wins
- Smashes steel, immune to damage, speed is manga_scaling.png. Luffy loses lol.

Okay well Kirbin just conceded this round so the win goes to Sabretooth.