Thought of the wrong thing but yeah I can agree with flare.
Mk 1 C is no joke.
Remilia touhou 6 normal reimuA (1cc run too)
Pretty sure i just beat it on adrenaline, no practice at all besides the few failed runs before.
Boutta make may eclipse replace that
This guy and that dog in the room with him are awful
General Argos when using a potato 200$ work laptop. I got him to 14 hp but then my laptop decided to go into low power mode, freezing me in place long enough to die.
i guess it depends, if the bindings (hollow knight) from p5 apply, then easily the collector all bindings, fuck his primal aspid
if they dont count but the hall of gods radiant mod counts then that radiant markoth (it took me 2 weeks, anyrad took me 2 days)
if none of that count, then easily nightmare king grimm, over 100 attempts, radiance took me less than 15
LCorp day 49 (real)
Ok now the hardest boss I am currently fighting is Sword Saint Isshin with Demon Bell and No Charm HE LITERALLY CHIPS THROUGH MY BLOCK AND DOES SO MUCH DAMAGE 
Just One Boss, anyone?
Which game is it I wanna play that
also King Calvus is hardest one I’ve fought ig haven’t really done any challenging boss fights
im back just to list all the things i’ve done
i beat touhou 6-8 on normal (although 6 and 8 were done a while ago, 7 is the recent one)
beat calvus with guns on a juggernaut file (~dark sea update)
beat hours as a vestige (not much but still)
got a perfect on may sf2 (no win, just a 1-2 with a perfect round)
uhh ig thats about it for boss fights, sadly i dont play enough games to have a good list like this
I actually beat that game
the mirror part is annoying but I think I just got lucky on the run I beat the boss
7.0 - 8.0 master core in Super Smash Bros. Wii U version
Maria with no armor no stats no buffs (wood magic 100%/20% blast and gun m1s only)
Cryogen for some reason, I hate how it’s fight is structured so much it pains me internally, I switched classes like 3 times fighting it.
Providence was pretty hard too, Scal and exos weren’t bad for me for some reason though.
Elius is easy, I soloed him 2 times in a row using the challenge I specified against maria in my previous post.
Oh also I forgot to add no overlevelling
that was from september 2023 
new hardest boss is Omega Death nacker Awakened Pre-nerf and Lilith and King minos
gg
Allusions, you need to do some stuff before you can fight it though.
Used to have to do an entire arg but you can get there pretty easily now
Alr, I’ll try it out if I remember
i beat him, took 250~ attempts
time to nohit him