(oh boy...this is going to be a long explanation, fun though)
@Legendofgenii @Enigma_the_Slimy_Boi
Oboro drank some water and cleared her throat. She looked at Gen and Salixa,
"In my land of Kamishima, the Yokai were able to stay in the mortal realm thanks to the intervention of a true deity, Tsukuyomi.
He created permanent torii gates, connecting the two planes. However, he could only do so at night, under the moonlight. So using some strange artifact, he created permanent night, underneath of the moon's most powerful state, the blood moon."
Tara interjected, "I can explain the artifact. It was a Chrono Egg, and this evil time wizard named Hansi gave it to Tsukuyomi. My quest was to destroy the Chrono Egg. It's a whole nother thing though. Go on O-chan."
Oboro took another sip, and nodded. "To answer your question, how could mortals kill gods?" She gestured to Yatagarasu, "Through him, the sun goddess Amaterasu sought me out, and she gave me a spell that could destroy the very essence of a Yokai."
She held up a spell tag with some mystical kanji on it. "With these, after I destroyed the body of a Yokai, then when their dama...er...soul came out, I could destroy them by casting this spell. Otherwise their soul would re-enter the spirit world and regenerate a body for them to once again walk the mortal world."
She brushed her cheek lightly, "I am also half-yokai. Which may be why I can use these."