Crow Sign 5, Veiling or Tornado 5, Guidance 3, lllusionary Dominance 1
A spellcaster build having stun, slow and strong damage at the same time. Crow Sign must be maxed as a method to stun enemy, and you pick one of Veiling or Tornado. Veiling is powerful, but you have to be close to a target for its duration while Tornado is relatively weak but AoE and slows opponents. The choice is up to you. You may consider getting damaging unique items such like Magic Stick as well.
Crow Sign 0 or 1 or 5, Guidance 1 or 3, Illusionary Dominance 1
A melee build relying on Aya's fastest move speed and attack speed. Whether to learn Crow Sign is up to you. Put rest of SPs into damage, move speed(if really needed for some reason), or MAX HP. She is one of the most squishy hero in the game so your item/SP setting would be better to be concentrated on survival instead of move speed and attack speed.