He is an anthropomorphic Serbian Hound like Ranko and Dragoljub and like other members with the most notable exception being Sefer he is another plainclothes member of the Alliance, in his soldier days as well as his time in the alliance he wears an ochre sweatshirt and black trousers but in his government time he has no change.
Mirko is shown to be just as heartless as a lot of other mobsters in the alliance and he is well known also for his sarcasm particularly with Vlastimir after meeting the Junta babies Vlastimir asks "Yeah, pretty hard on those two though?", he then replies, very sarcastically, with "Yeah, I'm eating my heart out (!)", he and Vlastimir are also shown to be close to each other with him being seemingly more careless than Vlastimir. His friend is not stupid but he does have a tendency to go crashing into hell with the consequences whereas Mirko likes to plan things out but it still pertains to the fact that he never hesitates to use physical violence and is evidently someone who will shoot first and ask questions later.
Like others he has had a long history of being in organized crime one of his most famous moments being Operation Fireflash, saying he will stop at nothing to get on board it even if it takes sabotaging rival aircraft. He is also someone who can drive a tug boat but his tendency to use violence in vehicles leads to him abandoning his tug boat as it catches fire, runs aground on a beach and explodes, his poor swimming also leads to him nearly drowning on at least two occasions before he gets picked up by the destroyer Dolphin which also reduces its slipstream to avoid drowning him. Mirko's violence also leads to him being a lot more heartless than Vlastimir and having a more tense relationship with a lot of allies, most of them female, than others. His disregard of children also defines him as not someone you want to show babies to and he also has little change in his government time.