Master Sigma is one of the best known tacticians around. When it comes to traps, none are better.
Calm and calculating, Sigma is one of the few Jedi members of the Chiss race. But just like her race, she puts her intelligence to use. Most of the other Jedi tend to stay away from her, since she is rather cold. Her student, Phi is very much like her. To the point they often have trouble dealing with others. Fortunately the other student, Tau is much better with people.
Sigma has the trademarked blue skin of the Chiss with black hair. She commands a dual ISD platform called the Rising Star. While no one likes to deal with her in a personal manner, once it gets to a battle, everyone trusts her judgement.