Merrick

Merrick is an Imperial Guard Sergeant of the 85th Vendoland in stationed in Subsector Aurelia during the timeline of the Dawn of War 2 series.

Why Merrick is badass

Merrick is voiced by Scott McNeil, which automatically makes him awesome, but no, it does not stop there, he's a prime example of what balls-of-steel guardsmen are all about. One thing that makes Merrick a total badass is that he is virtually unkillable, he survived through the first Tyranid invasion including the supposed suicide mission to the poison the Hive Mind, the Black Legion's incursion in the sector, another decade of non-stop combat with Chaos, Tyranid, Ork, and Eldar remnants in the sector, and upto the events of Retribution.

He gets killed in the first Tyranid mission by the Hive Tyrant, but we all know that the Tyranid ending can't possibly be canon, so it's no loss. More likely the first Tyranid mission happens just before the Imperial Guard mission starts. So the Hive Lord didn't finish him off, he just left him there to be picked up by Castor, who then proceeds to kill the hive lord, and the mere fact he survives getting 2 bone scythes shoved through him and surviving just adds to his undying awesomeness. He is also a snarky bugger, muttering under his breath about how much he'd like to shoot his superiors, and altogether speaking out frankly to them, mostly at Inquisitor Adrastia. One of the most badass things he does is call out Castor on his shit, beat the man to the ground, and stand defiant while LORD Commissar Bernn is HOLDING A GUN TO HIS HEAD!

Merrick also, despite seeing more Grimdark and combat than most guardsmen would see in their short services, cares a lot for his men. He cries manly tears after Typhon, and the rest of the Imperial Guard detachment stationed there, were obliterated by the Exterminatus fleet, which also led him to giving Castor a shot to the gut while going emotionally awesome on him.

In-game

Level him up to the point where he has no setup time for heavy weapons, and watch him tear apart whole units. If you give him the Autocannon with the random artillery barrage ability, Watch him solo missions

Machine Spirits don't seem to like his jury rigged repairs however.