Chapter Master Navassa Daspletus, leader to my DIY chapter, the Saurians.
They are a Salamander successor Chapter from the 8th Founding.
Long story "short", they hail from Triasic, a death world covered in tall, dense jungle, heavily populated by reptiles exactly alike the saurians of old Terra. Humans had lived in Triasic for almost 2 millenia, survivors from the first colonization attempt, but had experianced little in the way of development until the arrival of the Salamander fleet, mostly because some of the carnivorous Sauros, as they were named, seem to possess an evil cunning not unlike that of the orks, although much more basic, and mounted ambushes and attacks on human settlements as soon as they reached a significant size. This forced the human tribes to scatter, although they never lost contact between each other. The adoption of Triasic as a recruitment world by the Salamanders and, later, as the homeworld of the Saurians provided the humans with means of defense, and the population grew significantly, although the Chapters have always opted to maintain a constant air of threat to each individuals very existence, so as to breed tougher recruits.
Due to this grueling existence, the Saurians don't revere the great reptiles, as so many chapters do with their homeworlds' great beasts. Rather, they aim to become the top predators on Triasic, and each function on the chapter requires recruits to compete (in direct combat) with different types of Sauros and, finally, to prove their success in the same "fields" as the beasts. The Chapter Master position, specifically, has the aspirant hunt one of the giant herbivores that feed on the canopies, enter direct combat with a "rival" Dasptletusauros, a massive bipedal carnivore, many times the size of the biggest known theropods of Terra, survive a hunt by fellow brothers of the Chapter and, finally, if they've challenged the current Chapter Master for the place, engage him in close combat, to the death.
Navassa Daspletus was Chapter Master at the time of the Saurians' end, the most inspirational leader in the history of a Chapter in which leadership is conquered and settled by battle-prowess. A killing machine who took on champions and heavy tanks with the same sense of hunt, always emerging victorious until the Chapter's tragic demise, in the 38th millenium.