Shadow Isles vs The Void
 

The whole Shadow Isles thing is just so mysterious and we only know that the Void holds some scary beings based on Kassadin's Lore. So I heard speculations that the Shadow Isles is filled with undead creatures. I haven't seen any interaction between the two. My questions is, would a rivalry between the Shadow Isles and the Void make sense?
I just paired up the two because they are both so mysterious.

The Void is more alien/other dimension, while the Shadow Isles is more dark magic/necromancy

People say that the Void are really scary because they want to or have to potential to wipe everything out of existence but I noticed that we are waaay underestimating the beings that live in Runeterra, I mean Rengar is not from the void and yet he was still able to duel with Kha Zix to a draw, does that mean that if the Void ever does go to a war to destroy the world, the battle is not going to be one-sided and Valoran would actually stand a chance?

well i think that void is much stronger bicouse they are in other dimnsion and who knows what creatures lurk there. Cho is teror but who knows how looks ruler of void.

Khaz is most likely pond scum compared to some of the more powerful beings in the Void.

I see Kha'zix as more of a scout who is meant to go in first and adapt to a world. He's constantly evolving and learning how to be better suited at surviving and killing. So, scouts like Kha'zix would give the Void more information on how to invade a world. I don't think Kha'zix is reporting back or anything, but I believe that the Void is either an actual entity, or has a powerful leader who knows what all the individual Voidborn know.