Okay so, after a very long time i was finally able to create a main villain, but i cannot decide on backstory details
The main two ideas i managed to come up with are
I think the first. The only reason I chose this is because the second option is becoming a bit of a cliche, no joke. I think if he just had a recognizable trait, such as greed, there would be a non-cliche, perfectly palpable explanation for his evilness. If it's too basic for you, I recommend adding more drama throughout the story.
Don't want to be rude, have a nice day!
disgraced entity (or another important person) sounds legit. it feels like the person has motivation to drive his/her actions. you can also make the reader empathize with the character. you can take a few notes from one of final fantasy xv dlc, where the villain(ardyn) is actually a noble healer-king that was chosen by the crystal. but he absorbed too much darkness from people's soul to heal them. he was rejected to be the king by the crystal and became an immortal scourge to the planet. it's a pretty good example for a disgraced person