Isn't Mordekaiser the ruler of the shadow isles?
I just saw in the new map of runeterra about shadow isles. it's mentionned : "governance: none "
7 Comments
To be fair, there's multiple champs who can control the mist and it's corpses. 
and 
for example.
He controls a part of it,but I don't think that he controls the whole isles.
He controls some of the spirits but not all of them. Since now we know that the isles are not as small as we thought.
There is no strict government system in place. From my understanding, Mordekaiser can control spirits and the Mist, but he doesn’t rule over the Isles.
Not every spirit bows to him, and he’s also not the only one who can control spirits/the Mist.
Thanks for your answers, i hope we get some enlightment after his VGU (if it happens one day lol)
Morde controls the shadow isles yes. But it doesn't control it in an organized way or a specific one.
Morde would be on conquest to take it over for sure.