Biotic Mastery allows biotics to be more accurate with their biotic attributes. This attribute adds directly to the biotics base attack when using biotic powers. This does give the biotic another attack at -5 when the total of Base Attack and Biotic Mastery reaches +6, +11, or +16. This extra attack is only gained when the biotic is using biotic abilities, it can not be used for a combination of biotic and non-biotic abilities. This ability also adds to biotic rolls, including damage.
For Example: Leona has a Base Attack of 3 and a Biotic Mastery of 3, this gives her a total of +6, and allows her a second Biotic Attack at +1, she could use Warp at +6 and then Singularity at +1, but she could not Warp and shoot her pistol. Once her Base Attack reaches +6 she could Warp and shoot her pistol if she wished, but she would gain no extra attacks from her Biotic Mastery because her second action was not a biotic action.
Cost:2 Character points