Gunnery Sergeant ‘Stonetooth’ Harker

 'Stonetooth' Harker is a Gunnery Sergeant of the Catachan Jungle Fighters second regiment.

Official Canon
Harker is a veteran Jungle Fighter known for his incredible strength, even among the already tough Catachan regiment. He is able to carry a Heavy Bolter, something that normally only Space Marines in power armor can do. He also fought Tyranids bare-handed when he dropped his weapon.

TTS Canon
Harker served under Colonel 'Iron Hand' Straken when he and the rest of the regiment were saved and then recruited by Corvus Corax and Vulkan.