This is just the build that I use for Ezrael.

Greater Mark of Strength 9
I personally prefer AD runes to armor pen, just because it makes it easier to CS. Depending on the match up though, armor pen might be preferred.


Greater Seal of Resilience 9

These are cheap and help mitigate some damage you might take. Some people prefer MP regen for this slot, but if you manage your MP effectively, you shouldn't need the regen runes.


Greater Glyph of Warding 9

These runes are also cheap, but given how many supports like lulu, soraka, and sona poke constantly, and how some AD carries use magic-damage spells, they help reduce a lot of the damage you will take.

Greater Quintessence of Strength 3

Attack damage makes it easier to CS. Can be replaced with Armor Pen, if you prefer armor penetration.

I just went with a basic 21-9-0. 21 in offense so you can do more damage, and 9 in Defence so that you can come out ahead in trades. You might prefer to go 21-0-9 if you want the movement speed/MP regen and longer buff duration.

I personally go with flash Ignite. Ignite helps you in lane by shutting down the opponent's life steal, or the support's heal. Flash helps you position yourself more effectively.

If you want, you can get Heal or Cleanse instead.

Pros:
1. Good Poke
2. Has a built in flash
3. Essence Flux reduces enemy ASPD while boosting the ASPD of your team mates
4. Global Ult for checking objectives or securing kills

Cons:
1. Squishy
2. CC completely shuts you down
3. Dependent completely on Skill Shots
4. Looks female