Hello there, my nickname is Phos (Hotslogs profile-> https://www.hotslogs.com/Player/Profile?PlayerID=4627116). I am a casual player but i think i know this game and its heroes well enough to write some guides so you can try them and have some clue on what you are doing. Todays build is one i like and use it when i need to practice kiting or want to be braindead for the game (and get maximun damage of course, everyone wants maximun damage).

I have seen this build at many sites, it is my own with personal experience and tips.

Pros:
+ Great damage output.
+ Outplay potential due to its ultimate and extremely high damage at low hp.
+ Can pressure enemy heroes out of lanes with its high damage.
+ Some lane sustain thanks to his E("Regeneration").

Cons:
- 0 mobility and just a mild slow with his W("Twin Cleave").
- Hp lose in fights because of your passive ("Berserker"), which means you will be focused a lot.
- Have i meant you will be focused?

Lv1: "You Want Axe?" is in my opinion quite stupid if you can farm it efficiently because it gives more range and you are getting more and more damage and scaling into a beast for late game. Many players will prefer "Boneslicer" because it gives plain 20% increased damage, aoe marks and mana efficiency, everyone feel free to try both and get the one you are more comfortable with. "Arcanite Axes" is under the other 2 option for me.

Lv4: "Let the Killing Begin" needs no explanation, autoattack build and it gives attack speed, dunzo. "Troll's Blood" gives more sustain, but i just see it as a early lane talent and doesnt scale into later stages. "Headhunter" for me is more utility and maybe usefull when the enemy team has 2+ stealths.

Lv7: "Recklessness" its part of the core gameplay, for me Zul'jin (and more with this build) its basically playing with your health, and this talent gives you more damage at periods when you cant mantain youre passive; the gameplay its basically using passive until you get to 50% or less hp, get off the passive and start benefitting from "Recklessness", if you get higher than 50% hp then activate your passive if you see it appropiately and start all over again. "Vicious Assault" could be also usefull, but this is Axeman build so more auto attacks means you are doing it good. "Wrong Place Wrong Time" has no use, basically gives you more damage if you hit then in the apex (you are god if you hit more than 1).

Lv10: "Taz'dingo!" is the ultimate that will make you 1v3 the enemy team and be sad because global chat doesnt exist so you can read "noobchamp" "opop" etc etc... Makes you unkillable for 4 seconds which means that with your passive active and "Recklessness" active you will deal 25% from passive + 25% from "Recklessness" and an attack speed of actual level + team buffs + 99% from passive + 35% attack speed from "Ferocity"; basically you will melt everyone if you are not blinded or stuned. "Guillotine" can be usefull for picking up running heroes, but for me you need to take into consideration too many conditions (enemy hp, your hp, positioning, focus on you or not) to pick it.

Lv13: "Eye of Zul'jin" will be your choice, it makes your Q ("Grievous Throw") a movement speed buff which is ideal for chasing, juking and kiting. "Forest Medicine" could be used but i dont recommend it because 99% of the times you will be attacked and you wont benefit from it. "Voodoo Shuffle" can be used agains heavy root/slow team compositions, but even though i prefer the movement speed so i can juke all of it.

Lv16: "Ferocity" will make you attack faster with your passive activated, so basically more dps and more melting during "Taz'dingo!". "Lacerate" can be used if you are against low mobility heroes. "Swirling Death" will be never usefull in my opinion, so it doesnt exist.

Lv20: "Amani Resilience" will be your choice, it will make the 1v3 i mentioned earlier transform into a 1v4. As we didnt get "Guillotine" "Buzzsaw". "Ensnare" could have its value but i think the healing that "Amani Resilience" provides its way better.

At laning attack as often as you can enemy heroes to start acumulating "You Want Axe?" stacks, because you want it as soon as possible. Use your W to push lanes (stay diagonal to the minions and use W on mage, this way it will hit the mage and archers).

For teamfighting stay at the back and attack with passive until 50% hp, then 2 possibilities present: If you are having constant healing keep your passive activated, if not deactivate it and use "Recklessness", if you have the talent. Q as often as you can and try getting those improved hits with your passive.

The core gameplay of Zul'jin with this build is basically dealing as much damage as possible without dying (duh), it sounds stupid but if you loose hp to external factors that are not your passive is a lot of damage lost, thats why i said that this build is ideal to practice kiting and juking.

If you are lv 10 and you are facing another Zul'jin and you both have "Taz'dingo!" up try popping his ultimate first and you will win the 1v1. At lv 20 if you both have "Amani Resilience" then the 1v1 changes and you will win the 1v1 if you pop your ult first, as the healing from "Amani Resilience" is only applicable when the enemy team has hp remaining and the "Taz'dingo!" unkillable state doesnt count as hp remaining (even though you are at 1hp).

Hope you liked this guide and give it a try. If you have any questions leave it on the comments and i will see you in the Nexus (maybe?)