So with this guide you barely are going to use your W/Mystic Power-Defense, we are mostly focusing on dealing lots of damage and to even multi target your enemies while damaging them.
Remember to always enter a fight with the dash attack and then with the lighting field either to keep damaging or to retreat with its slowing.
First start with the Health/Power (Cosmic Belt and Atlantean Seal) which work very well with your passive as you will get bonuses from it.
Later game you use the blue scarab that also benefits you a lot as you get 2 energy with a landed basic attack while dealing extra PD.
The only need you need to do is to keep buying PD items as they give you moderate health bonus but remember to get any armor if neccesary.
Your ultimate should help you to wreck a group of enemies or escaping when you need it.