The Ionians knew a bit about the Void. The creatures that lived there were unholy, never go looking for them, in other words, they had a bit of basic knowledge.
The thing that they didn't know was that a Void portal would open, and coincidentally when the sentry shifts were going on.
So it was on both sides a surprise, both pleasant and shockingly horrible.
Now, to simply walk and bump into a big red thing with sharp teeth and green eyes is … well … not the best thing that would happen to you. Especially when they're from the Void.
The Ionians didn't know it was from the Void, although they would find that out soon enough.
20 minutes later, the whole shift was dead, with only the bones of their body on the ground. In another 3 minutes, not even the bones remained; only the red ground that was now soaked with blood.
When the next shift woke up, they wondered how they could have gotten such a good sleep.
Then, of course, they looked at the clock.
An hour later, they would arrive to see nothing of the sentries, only the red, slightly wet ground.
In the Plague Jungles
"OMNOMNOMNOMNOM!"
Wukong had returned to the Plague Jungles just in time to hear a strange noise as soon as he entered it. Funny, he thought, why are my monkeys not here? They're supposed to be….
And then the thing came out.
It wasn't from this world, Wukong was sure of that. If it was red, had green eyes, and looked really weird, it wasn't.
It had blood on its teeth too, and something that looked an awful lot like monkey fur.
Enraged that it was attacking his monkeys, he immediately sprang into action, summoning a Nimbus cloud to quickly travel the distance between him and Cho'Gath, then bashing him on the head.
He then immediately regretted being so close when the spikes came flying at him, impaling him. It was fatal, but he had to get back to his Master.
He knew the reason for the disappearance of the sentry guards.
Cho'Gath watched the strange monkey flee. He thought of pursuit, but he realized that it might inflict another painful bruise on the head. No, let the monkey run away, he would eat him later.
He groaned as he grew larger, and his bones and flesh became thicker and longer. The monkey he had digested … well … it seemed to be helping him, so whatever. Still, he hated fur.
He lumbered back to where the Voidlings were, and he would contact Swain.
They would destroy everything.
Then Cho'Gath realized he'd never tried the flesh of crows. He was rather eager to try it, but that could wait.
Until the world was all ashes, and the Void would take it.