Tarkus is your Tactical Marine Sergeant in the Dawn of War II campaign. His squad is the only one to deploy with your commander in the first mission. Squad Tarkus is quite possibly your most versatile unit. He is a strategically minded veteran of countless campaigns.
For his role Tarkus and his squad are definitely a jack-of-all-trades group. They can equip both melee and ranged equipment and will be reasonably functional with either but will be outclassed by dedicated ranged or melee squads. Their available skills and upgrades make them slightly more effective at range, and they also get a very high number of Accessory slots as well as eventually being able to convert equipped Frag Grenades into an infinite-use skill fueled by Energy instead of having a limited number of charges, which can be quite handy for clearing enemy units out of buildings.