by Kale » Mon Jun 07, 2010 5:01 am
Specifically; the fairy(?) in the Mage Guild teaches it. The Guild can be found in the Mirsen District, which is the left part of town just inside the gates. Just pick the conversation option that's something like 'spell learning' or 'skill learning', or whatever the game chose to call it.
For reference, the guild teaches skills to characters that they learn naturally as they level up. So, it's not of the utmost important that you learn Aura Bomb or any other specific skill from her. Your character will just learn it as they level up anyways. The same applies to any other skills that the fairy offers to teach; which the walkthrough does not cover.