This is my first build guide, and it's only because I was simply bored.

Don't take my word for a lot of things, I'm pretty low elo [S2], and am still learning the game.

Also, this build is less of a serious build, and more of a fun one. If you want a proper Ekko build, go onto some other League website and stare at those runes and the build. Or check out Arcsecond's runes if you're into a bruiser style Ekko in the Jungle. This build shouldn't be taken seriously, but if you want to, go ahead.

Grasp of the Undying

Simple. You will gain 5 Base HP upon procing it, along with dealing 4% bonus damage, and healing yourself for 2%.

Demolish

You're going to need this to break plates as fast you can. This especially helps when you've killed your laner, or you forced a back. Later on, you'll be able to splitpush effectively with this.

Shield Bash

This rune is better off if you're in the jungle. Due to the lack of a turret in the jungle, this rune will be much more helpful in doing extra damage, along with a slight bit of extra armor and MR.

Conditioning

You will simply become tankier after 10 minutes, along with becoming tankier as you complete your build.

Revitalize

This is the rune I take, but you can easily take a different one, like Overgrowth. I pick this rune simply to heal more with R, and have a bigger shield from W.

Transcendence

If you don't take this, you're doing 0 damage with the build. This rune is one of the 2 big reasons for this build.

Gathering Storm

You'll want to still do damage, so take this rune to get some additional AP later on in the game.

Strengths

Slightly safer laning phase
Safe even when slightly behind
Annoying to kill
Decent Damage
Great when there's no tank on your team
Great splitpushing potential
Adaptable depending on game status

Weaknesses

Significantly less damage than normal build
Build is weak when pathetically behind
Late game focused (30+ minutes)
Unable to fully run down enemies
Not invincible
Reliant on team when behind
Weaker when played Jungle

The choice on which role you play is up to you.

However, this build is significantly more suited for top lane, but can still somewhat work in the jungle. Jungle offers less farm, and is more reliant on you trying to get kills.