Seraph of the End: Red Scarlet

What if there is a third, neutral faction in the world of Seraph of the End? Luke Garcia of the Philippines had died in an earthquake and now, he was reincarnated into one of his favorite anime shows as Atsushi Ikari, an orphan. Now enlisted into the Imperial Demon Army, he begin to have doubts about his decision. But, he soon discovered that a spirit was within him, preventing him from making a contract with a demon and guiding, helping, and protecting him. Thanks to his spirit guardian, he can sense the aura of every creature, including demons and vampires, and use that as a weapon. But suddenly, he was pressured to join either the vampires or the demons. But then, the leader of the Red Scarlet Army, Yeager Ray, intervened and recruited him, causing Atsushi to make up his mind to join the Red Scarlet Army instead.
Now a soldier of the Red Scarlet Army, he soon discovers he is not alone in having a spirit guardian. There are also other elemental spirits lurking in the post-apocalyptic world that guide humans on how to survive, and they fight together against evil forces.
Soon enough, he would fall in love with Krul Tepes, the stepsister of Yeager. Can he navigate this new, strange world?