The story follows an egotistical hipster douchebag with spiky hair...
Who becomes bodyguard to a priestess...
Who possesses a monstrous power within, collecting parts of which comprises a majority of the events of the story...
and they begin a journey to find an ultimate weapon...
in order to combat a nearly omnipotent evil force plaguing their world.
Over the course of their adventure they befriend a cute blonde ostracized from society at large for their clan's beliefs...
and a quiet yet kind beast-man...
and fight several of the big bad evil power's minions.
Along the way there is much talk of the hero's rotten family member.
He is eventually revealed to be corrupted by the big bad, and the hero eventually confronts and defeats him to settle a long-standing grudge.
Eventually one of the church's agents is revealed to be an insane zealot...
which soon unfolds into the entire church being corrupt at its core...
and enacting a nihilistic plan to bring about the end of all life...
...which the priestess was an unwitting pawn in, as their "dark powers" are key to sustaining/restoring the big bad's existence.
The plot twists again when another character is revealed to be privy to the ultimate truth behind the nature of the game's events...
and reveals that the "big bad" and the "ultimate good" are one and the same, and the product of ancient man's hubris to boot.
The hero then finds the power to confront the big bad on equal terms through a particularly corny anime trope...
the group enters his body...
Inside, they confront the corrupted clergymen with delusions of godhood...
...and bring enlightenment, peace and eternal happiness to the world in a matter of months with no lingering conflict or hard feelings whatsoever. An extremely unbiased and realistic depiction of what would occur if an entire world's belief system and governmental body were completely and inexorably shattered, I'm sure. Every self-proclaimed supergenius atheist I've ever spoken to says that's exactly how it'll all go down someday soon, and they must be right because the braindead lapdogs they've bullied trained into mindlessly parroting it back to them on command all say so too! And if they're "in the majority" in a vicious hate-fueled dogpile on anyone who ever questions them debate, that means they're never wrong! So you'd best lie down, roll over and start kissing their asses, because when the dust from the endwar clears and they're finally crowned the all-knowing eternal emperors of mankind, the first ones in front of the death squads will be any surviving dregs who dared to tell them they were wrong about anything, ever! Boy, who'd ever guess that the one true path to flawless all-encompassing knowledge of spirit and universe is graduating high school with a 1.4 GPA, dropping out of whatever second-rate college daddy bribed to admit you after two semesters of majoring in partying, working the same thankless minimum wage retail job for fifteen years while watching Fight Club Joker twice a day and never having a lasting relationship or getting that promotion you "deserve" because you're a misanthropic narcissist who regards everyone else as either an obstacle in your path or a commodity to exploit for personal gain?
...though to Elena's credit, she at least spares us the indignity of an unbelievably shitty sequel with herself in the starring role where she is strongly implied to be in an incestuous relationship with her cousin.
So there you have it.