Observer

Requires: 70 Perception

You have a keen eye for Spells; when encountering a new Spell you spend an action to write it down. Over a safe rest you can then learn the Spell and add it to your list. For observing powers, roll an Arcana check against their power score to understand the Runes that would make the power. For powers made especially for enemies, give characters with observer a spell that is equivalent. Don’t just give them nothing.