Valadar Darkbane (4e Deity)
From D&D Wiki
Born into a society of elves that was constantly at war with the forces of the Pact of Ruin, Valadar was trained in the arts of scouting, healing, and warfare. He earned recognition through his selfless acts on and off the battlefield, including risking his life to save others on many occasions.
He finally met his end in an all out battle with the dark forces,where he was betrayed by the drow. They poisoned and massacred his already small band of warriors, and turned to the Shadows. With his final breath, Valadar sacrificed his life force to defeat the invading army and protect the souls of his fallen.
The gods, seeing his selfless, righteous act, decided to bestow upon him immortality as a demigod.