The Archangel Tyrael is a member of the legendary Angiris Council. He is the Archangel of Justice.
When Sanctuary was discovered by the Angiris Council, Tyrael was given the responsibility to lead the Heavenly Hosts in obliterating Sanctuary. He considered humans to be an abomination, much like Imperius, spawned by foul Demon blood with the pure Angel blood. But, when Uldyssian sacrificed himself to save not only the ones he loved, but also the entirety of Sanctuary, he had a change of heart. He felt that abominations cannot feel sorrow and therefore cannot sacrifice themselves.
When the vote was to be given to decide the fate of Sanctuary, he was among those who felt sympathetic towards the humans. In fact, it was his vote that saved Sanctuary from imminent destruction. Because, he was the last to vote, and before him, only Imperius had voted for the destruction of Sanctuary, while both Auriel and Itherael voted for its existence. But Malthael had not voted and if Tyrael had sided with Imperius, it would have resulted in a tie that would have destroyed Sanctuary nonetheless because of Imperius' insistence.
Because the humans' memories were wiped, none of them know the real face of the Archangel Tyrael. In fact, the Horadrim view him as the humans' Saviour and respect him.
More than once have the forces of Heaven ordered him not to interfere in mortal affairs, but he disobeyed those orders, feeling that without his help, the mortal realm would indeed succumb to the forces of The Burning Hells.
After the Dark Exile, he was the one responsible for creating the Horadrim in order to protect Sanctuary from the Prime Evils. He was the driving force behind the creation of the Soulstones. It is proven that he helped to capture Baal within Tal Rasha.
When Diablo was freed again, he chose to aid in his capture more directly. He even fought in hand-to-hand combat with the Dark Wanderer to stop the release of Baal. He failed because of Marius removing Baal's Soulstone from Tal Rasha's chest. He was ensnared by Baal's tentacles and bound to the Binding Stone in Tal Rasha's Chamber. The player character frees Tyrael and eventually travels to Pandemonium Fortress where he gives the player the quests to destroy Izual and finally Diablo himself. He is unable to help the player because he was severely weakened by Baal who damaged the forces that bind him to Sanctuary. After Diablo is defeated, he opens the portal to Harrogath.
He appears again in the Lord of Destruction, when Baal is defeated. He informs the player that the Worldstone, which was corrupted by Baal, must be destroyed in order to safeguard Sanctuary. His last appearance sees him destroying the Worldstone. His fate is not confirmed.
The rare stone Antyrael was named after him.
Tyrael has been missing for the last 20 years, and nobody has heard anything about him.