any context on why this is so difficult?
Halo 2 on the hardest difficulty is already CBT, especially when you encounter the Jackal snipers and their hyper-accurate precision, then, assuming you're playing the original Xbox version (which, Jervalin was), you have to first collect each and every skull/game modifier so you can then actually do the LASO run (legendary difficulty + all skulls on), which makes you have no HUD, no visible weapon, even tougher enemies who are always aware of your existence and fire their weapons faster while also chucking grenades like they're going out of style, and your shields don't recharge unless you punch an enemy, and weapons you pick up have much less ammo than they'd normally have
And there are some modifiers that don't up the difficulty but do add to the chaos, like one that causes enemies to explode like a plasma grenade (or just confetti in the MCC version), and one that increases the power/radius of explosions in general
Oh yeah, and you have to put up with all of that without dying once