Darkstar Leona.

pentakill is a band.. and kayle is an angel knight.. i dont know her lore much but theres lore for morg becoming a corrupt fallen angel, Sona's not a light champion, just a harp player or whatever she uses, Dark forge jarvan is closer to dragon slayer if anything else, but generally still not a light champion, Jayce, a scientist that is very over confident and cocky.. theres lore for him to be corrupted, Dreadknight garen, u got me there.. , Leona's Lore itself is pointed toward being a champion of light, a sun goddess or whatever she is , she uses the light for power.