Level 3
Memory Snatcher.
Whenever you would deal damage with Sneak Attack, you may choose to instead inflict one of the following effects.
Anxious Memory: Target is frightened of you until the start of your next turn.
Dissonant Memory: Target is silenced until the start of your next turn.
Resentful Memory: Target is slowed until the start of your next turn.
Additionally, you may change your Sneak Attack damage to psychic damage.
Psychic Perspective.
You have advantage on Insight checks to read another creature's emotions.
Level 7
Spiteful Soul.
Whenever you apply an effect through Memory Snatcher, you can deal half your normal sneak attack damage.
Level 11
Echoes of the Past.
Reaction (1/Encounter): When another creature within range 10 of you dies, you can absorb their memories granting you LVL temporary hp. When you do this, you also learn any information this creature may have known in its life time.
Level 15
Disconnected Link.
When you absorb a creature’s memories with your Echoes of the Past ability you can choose to erase any memories of it. Creatures on the same plane of existence lose any memory of the creature.