Scar is a very smart, stealthy Warrior Xenomorph that is usually the Queen's helper and likes to play cat-and-mouse with his victims also resembling felines in many ways such as being agile and likes to use acid and his razor sharp claws to kill.
Scar's name given to him by the Weyland Yutani Corp is Xenomorph 1212 and his purpose is to lead and destroy all that gets in his way of achieving that goal. Scar's favorite hobby is to kill either humans or Yutaja and will almost never kill another Xenomorph unless needed. One more thing about Scar is that he is also very sinister and manipulative.
Also Scar looks like a normal warrior, but is more thin and has a scar on the right side of his face given to him by a predator that tried to kill him.