Support
Make the first bomb ask the question and the second bomb grade the answer: tag the last-hit square, retreat square, or dive path with Q, then use W for the follow-up once they commit their dodge or route instead of autopiloting instant double-bomb every trade.
Start more fights with E than with hopeful bombs—speed the ally who becomes unfair with move speed or cripple the diver already coming in, because Zilean’s best games are the ones where one teammate gets to play the fight twice and the enemy has to finish the same kill twice.
R is not a vanity save for the prettiest carry scoreline; cast it on the champion the enemy has already committed to killing and who still changes the fight after standing back up, even if that is your bruiser or frontliner instead of your ADC.
In most fights, give E to the teammate whose next two seconds change the screen, not automatically to your ADC. If your bruiser or diver can actually touch their backline with one speed-up, that is often the best cast. If the enemy has already committed onto your carry, use it the other way and cripple the diver first. A simple rule helps: speed allies who are about to enter, slow enemies who have already entered. Re-check after W too. Zilean gets a lot from making the first E solve access and the second E solve the fight that access created.
Zilean stores time as Experience and can grant it to his allies. When he has enough Experience to finish an ally's level up, he can right-click them to impart it. Zilean receives as much Experience as he gives.
Tosses a bomb to target area that sticks to units that come near it (prioritizes Champions). It detonates after 3 seconds, dealing area of effect damage. If a Time Bomb is detonated early by another Time Bomb, it also stuns enemies.
Zilean can prepare himself for future confrontations, reducing the cooldowns of his other basic abilities.
Zilean bends time around any unit, decreasing an enemy's Move Speed or increasing an ally's Move Speed for a short time.
Zilean places a protective time rune on an allied champion, teleporting the champion back in time if they take lethal damage.
