I put a small update at the end of the item section that goes over it. In short, I love Abyssal Scepter now. I get it almost every game. The 10% CDR is just too good.

I am literally being carried through ranked from your guide XD. I've even got two mastery level 6 tokens already.

What are your thoughts on Abyssal Scepter now that the mage update came around? Abyssal gives 10% cdr and gives slightly more magic resist now. Also, do you have any tips on fighting Yasuo and the reworked Malzahar?

In the end, your goal in late game is to cause as much chaos as you can. Usually, that involves hitting the enemy back line hard enough that they need to leave the fight or die. With Liandry's Torment, I often have the damage to do that, and get kills with ignite. In games where I can't reliably hit the enemy back line (because they have blinks or dodge abilities), I look to counter engage or peel for the back line. I prefer the counter engage approach as it tends to catch the enemy back line off guard.

Luden's is a fun choice on Zac for sure. It adds a lot of burst to his damage up front. That said, I still think that a balanced Zac should have only one damage item. Without enough tankiness, you are prone to getting focused down in teamfights before your team can catch up and you get punished massively for missing elastic slingshot. There are a lot of good choices, Abyssal Sceptre, Void Staff, Luden's Echo and Liandry's Torment. I don't take Abyssal Scepter usually because I only buy one MR item and I would rather it be Banner of Command or Spirit Visage. I don't like Voidstaff, because you usually focus back-line carries in teamfights, not tanks. The reason why I would pick Liandry's Torment over Luden's Echo is because the magic pen amplifies his damage against squishy champions and the %hp damage gives Zac two sources of %hp damage in his kit (and most enemies hit by Zac will be cc'd so they will take double damage). The burn from Liandry's Torment will also be affecting them the whole fight and not just provide up front burst. I feel that Liandry's Torment gives you more power to kill squishy backliners and chunk everyone else at the same time. I will experiment with Luden's more just to be sure.

I really appreciate your guide. The guide and your videos have helped me dominate top lane with Zac.

Just wondering, what do you think about Luden's Echo on Zac? At max range, slingshot generates 90 charge (80 for distance, 10 for the cast). Having just 10 charge before jumping will allow procing Luden's Echo upon landing and follow up abilities will guarantee triggering it. The multiple bolts also synergize with his aoe damage.

Renekton can be a pain in the ***. He will win most trades and heal up as much as you do in the end. You need to do your best to cs and let him push you under tower where you are safe. If the wave is in a bad position, stand among the minions and try to bait him to trading with you. You will lose some health, but he will push the wave in the process allowing you to farm under tower. This lane is all about surviving and out scaling him in lane and having a bigger impact in teamfights. Even if you get a solid lead on him, don't assume you can win in an all in.
As for Zed, I love this lane. His damage is relatively low unless he is willing to use his shadow and if he does he leaves himself open to all in's and ganks. The key is trade with Stretching Strike and Unstable Matter when you can do so without him getting more then one auto attack in. If you feel safe (know enemy jungler isn't nearby), lead it with Elastic Slingshot. You also need to move in ways that make it hard for him to land his shuriken on you. Rush thornmail and ninja tabi and he will never be able to all in you without dying first.
For more details on how to handle the lanes, check out my youtube page where I have lots of examples of both matchups.
As for Stormraider's surge, I don't care for it. Zac engages with elastic slingshot and uses everything he has on landing. By the time Stormraider's surge kicks in, you have done most of your damage anyway. Not to mention your ult provides a speed boost already. Also, the only forms of cc you really worry about on zac are knock-ups and they can't be reduced by tenacity. I much prefer having the extra burst from Thunderlord's for Zac.

Hello, I really love your guide and wated to thank you for investing the time and work. I tested it ans instantly fell in Love with Zac, especially the 45% CDR.
but being a lowly silver scrub I have to ask: have you some adive for laning against renekton and Zed? These two are really testing my patcience at the moment. also what are your thoughts on the improved stormraiders surge?

Thanks! Grasp of the undying can work well on Zac. I just don't use it because it is not my style of play. It is great though that league does offer opportunities for two different play styles to do well like this. Keep up the good work and spread the gospel of Zac!

I love your guide - I was looking for in-depth studies in Zac mechanics and I finally found it :D I'm using masteries 12/0/18 - with "Grasp of the Undying" as my main mastery and "Oppressor" in Ferocity tree. Also using flash/tp, and "Dead Man's Plate". At this moment my placement series is 3-1 (only top, only Zac) with KDA 8.00. Screenshot below. Also subscribed to your YT channel :D. Thanks!

Thanks! I am always looking on ways I can improve the guide and will look into making the format a bit more readable. I highly recommend playing Zac as it is just so damn fun to land in the middle of the enemy team and cause chaos!