You gain the following benefits.
Ability Score Increase. Increase one ability score of your choice by 1, to a maximum of 20.
Merge with Shadows. While within Dim Light or Darkness , you can give yourself the Invisible condition as a Bonus Action.
Shadow Step. While Invisible, you can teleport between areas of Dim Light or Darkness. The condition ends on you immediately after you take an action, a Bonus Action, or a Reaction.
You can use this ability once per Long Rest.