Hathor Maat was the Captain of the 3rd Fellowship of the Thousand Sons Space Marine Legion during the Great Crusade. Maat was also the Magister Templi of the Pavoni. He escaped the Burning of Prospero as part of the contingent teleported from the planet by Magnus to the Eye of Terror.
Like his fellow captains, he had secondment with another legion. He is known to have spent time serving with the Emperor's Children Legion. Maat was noted to be exceptionally proud of an Oath of Moment attached to his breastplate. It had been personally carved by Fulgrim himself. [1b]. He was described as being vain and proud[1c] yet exceptionally handsome and stereotypically heroic looking with golden hair. [1d]
He was the Magister Templi of the Cult of Pavoni.[1e] His was a powerful psyker whose abilities focused primarily on the ability to heal [1f] although he was also known to have the ability to channel potent offensive lightning spells. [1g]. Maat was present with the Legion while serving as part of the 28th Expeditionary Fleet. And took part in the campaigns on Aghoru and Ark Reach Secundus. He participated in the failed defence of Prospero and was last noted to be present amongst the surviving members of the Thousand Sons who escaped to the Planet of Sorcerers.[1h]
Maat accompanied Ahriman on his quest to track down the shards of Magnus. However, he began to suffer from the flesh change. When they finally came to the shards of Magnus at Nikaea, the change began to take over him. Ahriman sacrificed him to Aforgomon, allowing the daemon to take over his body and manifest as the Fatewoven. 
- Hathor is the Egyptian goddess of, among other things, beauty. She is the Roman equivalent of Venus.
- 1: A Thousand Sons (Novel) by Graham McNeill
- 2 The Crimson King (Novel) Ch 23