Darnath Lysander
Darnath Lysander is the First Captain of the Imperial Fists Space Marine Chapter. He's a pretty cool dude. he wears yellow and doesn't afraid of anything. On the tabletop, he's feared as with 2+ and 3++ saves, Eternal Warrior and 4 wounds, this guy will not die. His Fist of Dorn will fuck up your armour. He can reroll bolters, despite not wielding one. He is also a techmarine, and can fortify ruins. Don't fuck with him, or he will murder you to death.
Backstory
Lysander has what might be one of the manliest back-stories of all time. His backstory begins as a kid of only 13. After surviving a Waaagh! and a heresy, he was recruited on Holy Terra because a captain thought he was the second coming of Dorn. He murdered what we can only assume were scores of chaos. He also boarded and captured the Eldar vessel named the Blood of Khaine. It is generally accepted that the Blood of Khaine had the Avatar of Khaine onboard, so we can only assume that Lysander tore it apart with his bare hands. Unfortunately, other factions began powergaming, trying to stop Lysander and company from doing the incredibly cheesy tactic of Drop-pods and Teleport homers, so the cultists used Warp dickery to mishap a squad of Terminators into a mountainside. As his Captain lay dying, he saw it fit to bestow Lysander with the Fist of Dorn, the coolest looking Thunder Hammer that ever was. Lysander then killed all of the stupid chaos cultists, then got promoted to Captain.
For years, Lysander terrorized the galaxy with the Fist of Dorn, deep striking himself and other Terminators into other enemy squads, just like how you play him tabletop. He later happened upon an Alpha Legion base, and tore them to shreds. All of them. Years later, as he was chilling with some Terminators on their way to Deep Strike some poor xenos, he got stuck in a warp storm and was lost. During this time stuck in the Warp storm, he probably roamed the warp with Draigo, beating the everloving shit out of whatever poor demon they met. A thousand years of demon-killing later, he re-emerged back into regular space. Chaos-held space. Immediately captured by Iron Warriors, they blew up his ship, then captured him and some of the survivors. The Iron Warriors then captured and tortured them for a few weeks on their fortress world of Malodrax. Tired of their shit, Lysander broke his way out of an Iron Warrior base with his bare hands, leaving a trail of death and destruction. He murdered fortress-world full of Chaos Space Marines specialized in fortified positions and close combat. Naked. After returning to Imperial space, he was screened for all types of daemonette STD's and for traces of heresy. Amazingly, he was clean. Being the oldest Space Marine alive, he was promoted back to captain of the first company. His first act was to go back to the Iron Warrior fortress world of Malodrax, and destroy all that remained. Due to his rampage earlier, he succeeded in destroying a few untoppled buildings and Chaos UNICEF.