Return of the King
Lord Admiral Aleksandr Gaius Blackthorne (Think Librarian without being in the Space Marines) was born more than 11 centuries ago. The oldest son of a powerful Rogue Trader, he was provided every consideration, training and opportunity to better himself. He served with distinction for more than 150 years with the Battle-fleet Gothic on the eastern front, engaged Tyranids and Tau before finally assuming the role of Rogue Trader. Blackthorne retired as a full Admiral of Battle Fleet Gothic. He only retired from that very successful military career when his father (Lord Socrates Blackthorne) decided to settle down and get rest on one of his pleasure planet estates in the imperial core.
The Blackthorne warrant is, like the Locke warrant, one of the originals granted by the Lords of Terra/Emperor while the Emperor yet strode the stars during the Age of Rebirth. His ancestor, known simply as Blackthorne, was as famous in his day, as is the current lord of that house.
Tall, dark, handsome. Approximately 7 ft tall, and of supremely heroic stature. Many who see him in his power armor mistake him for a member of the Adeptus Astartes. He is clearly psychic and radiates a powerful nimbus of power, which most Psykers would rather not display.
His flagship is the Divine Light