aside than she isn't human, but the mix of an spider and your resident nyarlathotep is somehow expected she don't really be the good guy here; worse, there aren't any legit good guys in this planet, only guilty victims and abusive executors:
-humans and demons are stuck forever in that rotten mudball because was their fault to abuse of MA energy, in fact demons was descendant of humans who used that energy in themselves
-pontimas is the black in all these shades of gray and the one who cause all of this shit because he wanted inmortality, thing that funily enough his "daughter", the future maou have.
-true dragons, these fuckers try to stop all (read: threatening with genocide) but when things went ogre they flew away with a good part of the rest of MA energy, worsening the situation
-sariel aka the system AI, a divine automaton (at least of how all angels act) with the mission of kill any who trespass the yellow line, dragons and titans equally; asigned to monitoring the strange activities she endend loving the living being and offering herself as a sacrifical sheep to restoring the planet, seeing how all souls die, rebirth only for dying again, slowly eroding to becoming nothing but energy, for her horror
-gyurestodynes, that inept dragon with a heart too soft for his own good, because love ended doing nothing (aside making a pact with the eldrich devil, sentencing his crush sariel in the process) but foolish things, like that peaceful paradise that ended destroyed anyways
-wrath, the very definition of victim with a river of blood behind, having his home and new family massacred he became so mad that ended destroyed anything in his path (because that ruler skill, wrath, make the user incapable to think rationaly when activated) incluyed that paradise said above
-suu, the designated hero with no spine, again because another rule skill he are unable to kill, even ones who really deserve it and suffer because that
-justin the pope, the definition of antihero and final enemy of kumo/shiro (who is another antihero in that point), having never forget all things happened before the game world (purgatory) he is adamant of human supervivency at all cost
-D, the true (ancient) god both in actions and behaviour, the devil who make the world a game just for fun (yes, she can fix the problem like nothing but who would want such a boring resolve?) and the engine for pontimas fuel of the story; also reason of why all class was iseai'd in the first place too
+the goalpoint itself, due overusing MA energy because some cunt, D in her infinite dickery said: all living being in this planet I hereby sentence to paid the debt with their souls, so go and transform the planet in a meatgrinder worthy to your average warhammer planet; the incentive? before fall existed a faction of countries who doesn't use MA energy (leading by guess who? justin, in that time president) because they noticed the future harm but in that point that thing works even better that oil, so that complains felt in deaf ears, using that D divide humanity in humans and demons in order to fight inbetween, fastfoward things are close to conclude (in red numbers also, thanks to pontimas and gyure) so the only options are kill all sides in a genocide war in order to restore the planet (kumo/maou side) or saving humans from that, with the cost of the planet (justin/gyure/any demon who isn't the maou side) and dying with them anyways
yep, even I know that exist several plotholes and nosenses