Diocletian Coros

Diocletian Coros was Tribune of the Custodes after Ra vanished, a Hykanatoi prefect who had already been of the Hetaeron and then had to become the man who organised the next wave into the Webway. He fought at the portal with Ra and the Emperor, got out, and received the visions Ra had been given. That was the promotion.

In the Siege he held the Inner Palace and the Eternity Gate with Sanguinius, then went aboard the Vengeful Spirit and was scattered into the dark with Valdor. He was brought down and still reached Lupercal's Court in time to see what Horus had left of his lord. He triggered the teleport home.

Terra kept him for the Heresy and not for the next ten thousand years. The Ten Thousand remember a tribune who wanted a good death and instead got the job of carrying the corpse back.