Tor Garadon
Tor Garadon is Captain of the Imperial Fists Third Company.
He was introduced during 6E's Sentinels of Terra Codex Supplement, acting as a sort of counter to First Captain Darnath Lysander's suicidal recklessness.
After the Third Company was nearly wiped out, Tor was called upon to rebuild the force using the Phalanx and manages, but just as they finished doing so, they fell under assault by Warsmith Shon'tu and his warband. They get the shit kicked out of them, but are saved by the Legion of the Damned
On Tabletop
Despite being a major focus of the Sentinels of Terra supplement, he never really got a proper ruleset. The closest we got to that was "The Spartean", his relic bolt pistol that didn't worry about cover when shooting.
Then he became another crosser of the Rubicon Primaris. In particular, Tor took to the Gravis armor for that termie-tough save and slapped a grav-gun on his suit.
In Other Media
Despite it being technically a temporary posting due to circumstances (the 3rd Company rebuilding), Tor Garadon has become the de-facto Imperial Fists commander stationed on The Phalanx due to his heroics at the Battle of Cadia for Battlefleet Gothic: Armada II.
He is present for the tutorial segment showing the Battle of Cadia, leading the Phalanx against the Blackstone Fortress Will of Eternity, though he plays no further part of the Imperial Campaign after that. He and the venerable battle fortress appear again in the Necron and Chaos campaigns however, and are credible threats in both.