How to counter Ekko.
1)Take an auto based DPS fighter(Aatrox, Tryndamere, Xin Zhoa) or someone with a massive amount of heals(Darius, Renekton)
2)Trade.
3)Profit.
How it works:
He's a tank that masters at short trades or all out trades, the only issue with him is that he cant heal afterwards without ulting. What does this mean for most top laners?
Well, Their are many kinds of top laners, each unique to a different type of team dynamic.
There are tanks, who can be very powerful in lane by out tanking the enemy and beating them with base health, but this often exposes them to taking a lot of damage from poke, and most tanks lack sustain. These guys love farming up and causing big team fights to soak up damage. However, they lack impact and usually rely on a single skill, and the ult, of course.
There are fighters, Who are often powerful in lane, usually being a form of dueling bully, they dont have a ton of health, but they sure as hell gonna hurt a lot more, they have more impact in roaming and small fights than tanks, and have multiple abilities to pump it out.
There are squishes, who have very high damage output, they usually are ranged, however if they are melee, they usually have abilities to avoid/block damage(hi Riven), most of them rely on winning lane so they can continue to dominate, and they have less roam potencial than fighters.
Now which category is Ekko in as a toplaner (I see him top more than mid)
Well he's a tank, good. but not only is he a tank, but he's also very mobile and fits into a sub-class of the Fighter, the Skirmisher. Skirmishers have utility and powerful abilities to win trades quickly or die and are technically "overloaded," most mages are overloaded with powerful spells for most situation, some Skirmishers that come off the top or my mind are Pantheon, Gankplank, and Jayce. But tank Ekko is different Hes gonn dive and not die, pumping out some really quick damage with his eq passive, then choose wether or not to disengage, cuase as a tank, hes gonna have less damage, but more(much more) survivability.
What does this mean for Ekko?
As a tank with an overloaded kit, he has so many options to skirmish and win based of survivability, as most tanks can get kited by squishies and poked, he's gonna be in their faces and smashing them like tf2 scout. Hence eliminating a tank counter, a tank against a tank is a really boring match, but Ekko, who provides endless utility, he's gonna dance around the tank like he doesn't even care. Hence eliminating just playing it out, and fighters, namely, Skirmishes lose to him purely off health difference. He seems invincible right? Well thats the thing, as a tank, he lacks sustain, to only way for him to drag fights on is to out health his opponent, and if his opponent out heals his damage and sustains in lane, he can't win! thats why darius, reneckton, aatrox, xin zhao and tryndamere beat him.