ninjago season 2 ep 10 "the dark Servant"

After meeting Malachar, the ninjas return to the monastery with Lloyd. But their break is interrupted when Vexor, Malachar’s loyal servant, arrives and attacks them with his dark purple powers. The ninjas fight back, but Vexor traps some of them with shadow chains. Lloyd uses his green energy to free them, forcing Vexor to retreat. The ninjas realize that Malachar isn't their only threat.