This is my guide for Zilean I am still looking for the best build for every situation INGAME : Dommeno / PrinceOfPotatoYoutube : https://www.youtube.com/channel/UCMKBOQNH2v0XvJ_EHYCyaQw
this is the best build I played so far and it got me from silver 5 to gold 5 in 70 games with a 70 % winrate
damn the ap Zilean supports who try to carry
this build gives your adc to much help so he basically never dies and you can stun for days with the cdr and mana you will feel like IS with all these bombs and you cant get bursted because you are tanky so the enemies cant focus you and you can ult your carries

ask as many questions as you want I will answere them as good as I can
If I spelled something wrong please write it gently into the comment section

More information about items and reasons are coming soon ;)

You can play Zilean with basically every adc but keep in mind that Zilean is weak at the earlygame so if you play with vayne get rdy for losing lane (if the enemies arent stupid :P)

Pros

- Works with basically every adc
- Can carry games without building dmg
- Strong late/midgame
- Amazing Aoe Stun
- Strong Ult
- Strongest Slow/Speed ingame
- FAST AS FK BOIIII
- Low Cooldowns

Cons

- Weak earlygame
- No Sustain
- Hard to play( you have to know what to do with your abilities because there are so many things you can do)
- You need good reflexes for good Ults and Doublebombs