Idk, we've never had any hellish stuff in the lore before and while being in-game, it should still represent the character itself.
Imagine if we had "That feeling when you go to the bathroom in the morning" for Xerath's ultimate or something.
Or "Heavenly Guidance" for Kayle's W and so on..
Hellbent doesn't necesarily mean hellish or demonic, the definition of the phrase hellbent is "determined to complete a task at all costs" which is how aatrox should feel when he's got the revive, it's when he should be going the most ham
Hell's been a concept at the very least in League since Shadow and Fortune, when Rafen says "Seven hells", so at the very least conceptually they have some kind of hell. Whether or not there's an ACTUAL Hell remains to be seen, though it depends on how spirits and the afterlife work, a concept that we have yet to see since we've only heard mumblings about the spirit realm and Kindred's not bothered about any afterlife.
umm... hellbent is an adjective that means determined.
