Blood of Glasya

Thanks to some unholy agreement or curse placed on your family, the blood of the Archdevil Glasya courses through your veins. Your fiendish ancestry and close connection to the imprisoned Princess of the Nine Hells makes you innately well-suited to life in Malbolge. You gain increased dexterity, as well as the ability to open locks using Knock once per long rest. 

•  Increase your Dexterity score by 1.
• Gain access to the Knock. You can cast this spell once per long rest without expending a spell slot.