Lesser Arcanum - Valerian

Warlock Additional Feature - 5th level 

Starting at 5th level, you can choose a spell of your subclass expanded spell list. You may cast it once per long rest without expending a spell slot. This spell has to be of 1st level, but you can choose a 2nd level spell to cast in the same way at 7th level, a 3rd level spell at 9th, a 4th at 13th, and a 5th at 15th. You can have one Lesser Arcanum spell per spell level.