Prime TUI Shingen is the Strongest Character we have seen.

No questions about it about Prime TUI Shingen that fought the fist's is the strongest character in lookism without a doubt.

We don't know enough to fully say for sure and until we get the full 0th gen backstory and understand everything we can't lock this in yet.

But going off context, for now Shingen is the strongest character we know of.

First is the boost that TUI offers. We saw from Gun that TUI made him go from struggling versus goo, and needing to go all out verus Johan to being able to beat Gun and then fight ui daniel right after, even though he was knocked out of TUI, I fully believe a fresh Gun in TUI could have beaten ui daniel there. TUI is just a op powerup that easily makes someone even near on death be able to hang with top tiers.

So Shingen who in base UI was ripping limbs off, with TUI is massively powerful and is proably worth 99% of the forces of the Yamazaki. Of course this is is just a theory though but you can't deny that Shingen alone is worth a major amount of the yamazaki fighting forces.

Also base Shingen is most likey around current Gun level. At least he's a top tier so even without TUI he is still very strong.

Also you need to keep in mind it's most likey been years since the fist and yamazaki fight happened. The Gap we see is the old one not the one in his prime. So this Shingen is also one not in his prime and most likey very old. Also due to his depression we can safely say this Shingen is much weaker than the prime version of him.

However that old Shingen in TUI was tanking blows from another powerful UI users, a fatal blow, and rain's of swords. He didnt even fight to win just to protect. Now imagine that but much stronger.

Shingen alone was most likey around the same as fist's top tiers. I see it as fist's top tiers needed to jump him to beat him and send him back to japan.

Ofc a lot of this is just if, and guesses but I see this dude as the current peak untill new chapters comes out.