Thief's knowledge

Rogue, 4th level

You have tried stealing many magical items, and because of that you've studied their properties and uses.   When you choose this power, you have advantage on arcana checks related to figuring out how magical items work, their properties such as charges, and seeing if any spells are affecting it.   If you do not already have proficiency in it, you gain proficiency in aracana. If you already did, you gain expertise in the arcana skill.