Mentor Assassin Beta was one of three assassin droids that were controlled by the droid consciousness Mentor. Alongside Zeta and Theta it confronted the strike team sent to Zadd to halt Mentor's plans for droid revolution. Zeta, and its fellows, engaged in combat by sharing abilities, passing a set of defensive shields from one shell to another. In spite of this tactic, it was destroyed by the strike team.

Beta did not have an independent consciousness at the time it was destroyed by the strike team, rather it was controlled by a portion of Mentor's awareness. As such, only the droid body can be said to have been destroyed.