Lurk

Basically Rogue-like Psionic class, except we already had the Psychic Rogue which is mostly superior to the Lurk with better power access and Backstab dice progression. The Lurk gets a lot more flexibility thanks to its wide access to augments, allowing it to apply crits and backstab damage to undead and constructs, or apply backstab damage without needing to set it up. This is resource intensive and means burning Power Points as well as it lacking good backstab dice without burning pp and multiclassing or taking prestige levels in Assassin. Where as the psionic rogue gets better Backstab dice progression and doesn't need to burn so much PP to bring the pain.