Hello and welcome to this Guide. I am quite a new guide publisher but I wanted to create a unique one. Hail of Blades Mordekaiser is a bit experimental but I have found it working very good. Read more on the keystone in the rune section.

This guide is still new, so leave feedback if there is anything wrong that I can fix.

& will be your typical choice of summoner spells for top. You don't need anything else.

Primary - Domination
The thing with Hail of Blades is that you can auto-attack 3 times in a short period. This is great for Mordekaiser as his Q procs 3 times with auto-attacks. With Hail of Blades, Mordekaiser can proc 3 Qs in a short period of time and do a lot of burst damage before the enemy gets the chance to escape. Without this rune, it was a lot harder to get those Qs off on the enemy.

Hail of Blades is still pretty new and experimental but it got buffed in both patch 8.12 and 8.13 which made it alot better. That's why I think it can be a good option over Summon Aery.

Taste of Blood is the only option in the tree that Mordekaiser can use efficiently. Same thing goes for Eyeball Collection.
Ultimate Hunter is newly added to their tree and fits better than previously used Ravenous Hunter.

Secondary - Sorcery
Nimbus Cloak gives you Movement Speed after using your ultimate. It gives Mordekaiser some extra movement speed to chase his target.
Celerity is a good option for Mordekaiser as he needs as much mobility as he can get.
Scorch can be picked instead of Celerity for more early game damage.