Champions

[King B]

Zilean's slow is really good for picking off that one person that's straggling. It's a DEVASTATING slow and can easily turn around a fight or a game for you. Runes and masteries are fairly simple. Once you get blue you're unstoppable mid game and laning phase. His scaling falls off really hard late game, but he has so much utility in his ult and slow/haste that it doesn't hit him that hard. You just gotta make sure you make the transition from AP Carry to backline support/ap damage. Cast rewind a lot whenever you're not doing anything, it refreshes the cooldown of an otherwise very long cooldown ult.

A general build on him would be: Merc treads, RoA, Void Staff, Rylai's, Deathcap and Frozen heart or Archangel's Staff.

Also when you're Zilean, you have to take into account the experience advantage that you have against your lane opponent. I would play him very aggressive mid lane and secure big advantages in early trades. Zilean's bomb with 3 points in it is disgusting.