[Hatorade]

Aion: Tower of Eternity Preview - Page 1 // MMO /// Eurogamer

Stigmas stones, which drop from monsters or are handed out as quest rewards, are skills from other classes, and can be equipped by any class with very few restrictions. They might allow a Warrior to equip a Mage's spellbook and cast offensive magic (spellcasting is accompanied with a neat page-flipping animation), or a Mage to wear a Warrior's plate armour. You can collect any number of Stigma stones, but you can only equip a handful at a time; these can't be hot-swapped in combat, but can be changed by visiting a trainer and paying a small in-game fee. The most powerful skills will be rare drops, equivalent to a fine weapon or piece of armour; like other loot, some can be traded, and some will bind to the character.

Good read.