Cethgus has been in countless duels and battles over his career in the Brotherhood. With that experience comes a keen awareness and understanding of the various intricacies and strategies of combat. This manifests itself when studying an individual opponent's tendencies in swordplay or the strategies of an entire army, giving him a unique insight into dissecting an enemy. That same insight often gets overlooked given his martial and almost brute-like nature, and he often surprises those who assume so with an idea or suggestion on the Battlefield. His knowledge is a combination of what he has studied or seen, but non-conventional tactics have given him pause before. He also has problems joining in on conversations that don't involve warfare, which makes it hard to relate to others.

Cethgus seems, in all of his actions, to be honorable and prideful. After the training that he took, he prefers to fight head on instead of from the shadows. No matter the price he has to pay he always takes things seriously, and would rather be killed than lose his honour in combat.

Cethgus is a devout member of Naga Sadow, the Clan that has given him everything in his life. A clan he has a bond with that can never be broken. His devotion to his Clan is such that he would lay down his life to protect Naga Sadow from harm, be it from within or without. This attitude can cloud his ability to be objective, towards members of other Clans or Houses, or from individuals he believes do not work for the betterment of Naga Sadow like he does, causing a gulf between himself and less overt members.

Cethgus has developed into a mature and serious leader. He is easily annoyed by others joking around or drawing unneeded attention to themselves and prefers to always remain focused on the matter at hand. Having grown into the responsibilities of his positions, Cethgus now hates anything that he deems childish. He prefers to be treated with respect and gets irritated when not addressed formally or by one of his titles. Despite his distaste for shenanigans, he will still go to extremes to protect his family and his members, but will try and mask his care with blunt indifference.

Cethgus is the veteran of countless battles and warfare. Through each campaign, his lightsaber has always been at his side to carve a path towards his goals. As he rose through the ranks, his dedication to using only his lightsabers raised more than a few eyebrows. Now wielding two custom blades, the Primarch has achieved an adept proficiency in battle when wielding his lightsabers. His sabers act as an extension of his being, responding instantly to the whims of muscles honed in the crucible of combat. Depending on the flow of battle, he will switch between his two styles seemingly at random to keep his opponent guessing. This focus has left him with little trained experience with other weapons, and put him at a disadvantage when facing a ranged opponent.

A warriors body is hard to achieve, but Cethgus is an Obelisk to his core, and has spent years fine tuning his body to endure the hardships of battle. Daily sparring, conditioning, and always fighting those who were stronger than him has burned away any semblance of weakness in the rigours of combat. While his resilience is heightened, he also pushes himself to his limit, and pays the price afterward by recovering slower than others from major injuries.