Basically this Zeratul build is all about going in and out of stealth and cleaving the **** out of everyone. Cleave is amazing with this build and you'll be a great asset in team fights with all this aoe damage. This build allows you to even take merc camps by yourself because of the high cleave damage and cleave DoT. Both of Zeratul's ults are good but for different reasons (see talents). He comes with a ranged slow, and also a very nice escape.

Tier 1

GREATER CLEAVE
This talent makes Zeratul's cleave able to hit many more enemies and it's great for teamfights and taking out minions.

Tier 2

GATHERING POWER
This talent is amazing for teamfights and straight up dealing crazy hero damage. Staying alive is key, so if you are a risky player and die alot, i suggest not taking it.

SUSTAINED ANOMALY
This talent is a great talent for focusing more on minions, mercs, or just the fact that you die alot so Gathering Power is useless for you. ;)

Tier 3

VOID SLASH
I love this talent because i like to open with cleave right out of stealth and hit multiple enemies. This does increased damage and combined with ASSASSIN'S BLADE and RENDING CLEAVE it is amazing for multiple enemies and creates great pressure on enemies.

Tier 4

This talent tree is basically your choice, if you are going for a hero destroying build go with SHADOW ASSAULT (my choice), or if you're going for helping your team in team fights or escaping, VOID PRISON is a great choice.

Tier 5

ASSASSIN'S BLADE
This talent is just completely amazing. First of all you get increased stealthed speed so no one is running from you. Secondly, You get the increased attack speed when coming out of stealth. This build is all about breaking stealth and just doing as much damage as possible to as many enemies as possible and then Blinking away. ;)

Tier 6

RENDING CLEAVE
This talent along with ASSASSIN'S BLADE, and VOID SLASH is just completely pwnage and everyone shall fear you. As soon as you pop up with your Cleave everyone will get hit for a ton and have a nasty DoT on them.

Tier 7

This tier set all depends on what you take in tier 4. If you took SHADOW ASSAULT, Nerazim Fury is completely beast because it lasts 50% longer and grants crazy life steal. If you took VOID PRISON, Protective Prison is great because it makes Void Prison so it doesnt mess up your allies anymore. ;) Rewind is another great choice because it would allow you to get off two cleaves in a succession or allow you to blink twice to dodge all enemies.

Zeratul is a great assassin hero and he can be built many different ways. My favorite way to play him is the sneaky cleavy build that specializes in wrecking all enemy heroes and doing intense damage. You can also build him to make his Singularity Spike deal more damage and AoE damage. Or you can even build him up to kind of support the team with void prison and such. He is an amazing hero overall and this build is mainly for just straight wrecking your enemies with stealthy cleavy goodness.

Basically this is just a fun build that is based on Singularity Spike. Just talent everything into making your singularity spike intense and annoying as hell. It'll do aoe damage and slow everyone, you can cast it without breaking stealth, you can cast two in a succession, and then you can rewind and do it all again! Line everyone up with your void prison, then unleash a ton of aoe bombs on everyone!!!