[@KatherinWinter]
Basically he can power up his physical attacks with fire lightning and ice.
That's using his own energy and the energy around him. 

Lightning can arc and be thrown. It also speeds him up.
White flames can ignite things, burn those that's touch him and gives him a boost to str.
Cold is slower acting and moving, he can bolster his defence or freeze things he touches.

Lastly Azerus can draw energy from a foe (usually unexpecting) it leaves them feeling lethargic and tired. Weak even. It takes a while to suck out someone's energy and Aspeth favours to do it prior to battle secretively or by drawing out the fight knowing the longer it goes the weaker they will slowly get.