There are corruption and lotus branches of the feat tree. Assigning points to the corruption branch give the assassin unholy DoTs, life and stamina leeches, and they shore up his armor rating to a degree. Abilities triggered from this branch will require varying numbers of soul fragments, which are gained by successfully completing combos.

While the corruption tree works to make the assassin a little more hardy, the lotus tree veers more into the realm of poison, concentrating on multiple DoTs and chances to do additional damage. Though it's a higher damage output in lotus, the assassin only gets one heal ability this way, so he'll be more fragile. Also in this branch, the lower a target's health, the more powerful the assassin becomes. That doesn't mean the lotus branch is all about killing, though, as the assassin eventually gets an AoE confuse ability by continuing to assign points in this line.