LPSAD has not shown any feat that would let Fiamma fight on Aleister's level.

Almost destroying the continent. Should be a good fight.

He just gets blitzed either way. You said yourself that the fight happens with all of them bloodlusted,

Which I didn't deny.

Yes Fiamma beats Saints, but by the time Aleister does that, Fiamma's already dead.

Why wouldn't kamijou protect him during that time Aleister Finna kill him. It should be noted that Kamijou deflected magical bullets from Aleister spiritual tripping. It's not a far Reach to say that kamijou comes in time to protect Fiamma from death. Or better yet Kamisato takes him by surprise and World rejects him.

don't think you realise the speed difference between 2 physically normal humans and Saints.

I realize completely. Dragon shell and or fisheggs should pack up Aleister before he even have any time to think.

Okay say Fiamma does die.

Aleister have no way of countering fisheggs and needed misaki of all people to help restrict him. While he's fighting fisheggs, Kamisato comes in to world rejects him, and Don't say he doesn't because he caught magic gods off guard. And orginal Aleister didn't even know of the existence of World Rejecter during this time, and would theoretically fail to see him as a threat.