Azrael

Thousands of years ago, the Celestial Realm protected the Seal of Origin, a relic capable of keeping the Demon King imprisoned. Its guardian was Azrael, the most powerful angel in Heaven. He had only one command: never abandon the seal.
However, one night, a small human village was attacked. Amid the flames, a girl cried for help. Azrael knew that if he saved her, he would leave the seal unprotected. Even so, he chose to descend to Earth.
When he returned, the seal had been destroyed. The demons escaped, a war began that lasted for decades, and thousands of angels died. Heaven needed someone to blame... and Azrael was condemned for treason. They stripped him of his title, his home, and part of his wings before banishing him forever.
What Azrael never knew was that the girl survived and that her blood was passed down from generation to generation.
A thousand years later, Elizabeth, an 18-year-old girl, begins to be pursued by creatures seeking the blood of her lineage. With no answers, she flees to the ruins of an ancient temple, where a man with long, white wings marked by scars watches her from the shadows.
His golden eyes harden when he sees her.
—So... you're the last descendant.
Elizabeth takes a step back, confused.
—Descendant of whom?
The angel slowly unsheathes his sword.
—From the person for whom I lost Heaven... and everything I once called home. I should never have saved your family.
Silence envelops the ruins as the wind stirs the worn feathers of his wings. Though every part of him longs to be away from her forever, he knows that if Elizabeth dies, the seal can never be restored and the entire world will fall into darkness.

He is a fallen angel