Based on the lore and the champions themselves, it seems to me as if eve and yorick have no real(or at least truly relevant) connection to hecarim and mordekaiser other than the shadow isles as their place of residence/origin.

However, mord and hec do seem connected not only by whatever official military forces the shadow isles may actually have, but also i think they both may wield the powers of 2 of the 4 horsemen of the apocalypse.

You could make a case for yorick too, but to me he actually seems to draw some powers and abilities from all 4 horsemen when he summons ghouls, perhaps acting as an emissary or servant of some sort to them rather than being a horseman himself. It cant be coincidence that when yorick uses omen of war the ghoul is not only faster than the rest, but also grants yorick increased movement speed a la hecarim. On the other hand, when he uses omen of death he gets to summon a revenant of a champion, in a somewhat similar, although not as strong way as the souls mordekaiser controls when he slays enemies.

If this line of thought holds any truth at all, we have yet to see the famine and conquest/pestilence based champions.

Would love to have some red input on this hypothesis and to read the thoughts of the community as well. Thanks.

nice theory sounds like it would be fun thing to explore seeing as how the shadow isles are kind of hinted as a more or less sinister/hell like place or w/e

So hecarim is death, and mordekaiser is strife? Sounds about right to me. I personally would love to see a few more biblical references in league. Another two horseman like characters seem to fit quite well and I think your theory is sound! I think yorick more fits in to the bill of the ferryman through the river styx. Constantly working to usher the dead to their final resting place but beyond that no real goal or motivation.

I always thought 'Kaiser was the horseman of Pestilence, if his lore is anything to go by. And Hec is most likely either War or Death, I'm not really sure about that. He has a personality fitting of War, being the bloodthirsty berserker that he is.

But I'm really looking forward to the other two/three; depending on how you interpret the apocalypse it's either Pestilence or Conquest, having both however would be totally radical.

Hecarim is closest to War, unlike Mordekaiser who more subtly crept into the League he barreled through and slew all in his path, hinting at coming conflict. Mordekaiser is most likely Conquest, who is linked to disease and plague (although so is Death). Conquest is seen as more of a military figure, mirrored by Mordekaiser's air as some sort of general. I think that if this is a valid theory, we will see Famine next, then Death.

Nope... The whole horseman title thing has been applied to all of Yorick's ghouls... Would b too repetitive of Riot to do it AGAIN.

Well, Hec and Morde are both fairly obvious references to the Horsemen, either in their innate abilities (Morde with his touch of disease), behavior (Hec as a crazy blood knight and Morde enjoying the plague ridden slums) or their appearence (Hec for obvious reasons).
And I think that giving champions a symbolic group as the horsemen is interesting, especially for Valoran as a whole, with the Shadow Isles slowly starting their attacks. I think they didn't really think about that when they made Yorick. I am cool if Riot is going to use that topic again, since it has a lot of story potential.

I think Morde is fairly explicitly a disease spreader and linked to that entire theme of what Pestilence is usually portrayed as.

How is Yorick not Death? Also, very cool analysis!

Wasn't it stated a while back that both Morde and Herc's goals were the same, but both weren't in agreement on how to achieve that goal? I always like to fantasize that Fiddlesticks was from the Shadow Isles as well, but he isn't. Though he would fit in with that bunch of champions.

While Yorick might have come from the Shadow Isles, considering his lore it's doubtful he shares the same purpose as Morde and Hec.