Mystical Essence of Wind is part of the Xegony tower key quest. You need the four different essences from the four PoA avatars and the quest container from the air drake in PoT to make the key. You will probably find that the Mystical Essence of Dust is the bottle neck for this quest. The Avatar of Dust script is particularly annoying, unless of course you like spiders. Only one member in a group needs the key to get the group to Xegony's tower.
Actually you are incorrect. The HP stun ia a targeted AE (meaning it is an AE centered on the person currently holding aggro, which is generally going to be the MT). There is no such thing as a directional AE.
Actually, you are both incorrect and correct. There is a mob in halls of honor, called "a Rabid Wrulon" who has an AE that's directional and will drain your mana so fast your head spins.
I love this fight. We don't wall him, I get full bow hits almost every shot and my archery DPS goes up up up (stupid mobs with stupid frontal AEs get walled and make Rangers everywhere cry), plus i get up on the wall and feel taller than everyone else.