Does that mean he lords over Kindred? In fact, what's Mordekaiser's relationships with the "Grim Reaper" of League? Could it be the title change has something to do with the new champion and Riot's keeping a secret of it?
It's no longer Lord of Death, it's now The Iron Revenant. Go here for more info: http://boards.na.leagueoflegends.com/en/c/story-art/kqtsql6J-shadow-isles-and-death-why-mordes-title-feels-wrong-and-more-making-everyone-happy-kinda?comment=00030003
Probably is to reflect on the fact that Children of the Grave (his most iconic ability) allows him to enslave the souls of others, and thus lording over the dead.
Its most likely more because he is a high ranking member of the shadow isles,who uses death magic and can enslave the souls of the dead.
I mean the shadow isles are also referred to as a land of death,yet it is a land that actually avoids kindred.
Death has many aspects and kindred is only a part of it(the dying part to be precise)
