Ok... How many times has Yuri re-lived this story? At least once with each love interest I assume. And what is she? Just a character stuck in a curse or something? Or a transmigrator as well? What is that voice telling her what to do and that she must catch them all? And why does Yuri have to re-live this over and over again?
At least this brings 1 answer: why Yuri keeps getting kidnapped and in danger when she herself is a powerful magic user. Because she is bound by the system and is forced to follow certain events, whether she likes it or not.
I hope Melissa can find a way to break this endless cycle of suffering. Yuri deserves better.
So first of all, what our MC is seeing is a flashback. It seems like the angels/wingdims? were trying to take control or kill all the monsters. And they were wining until the Shadow Monarch showed up and turned the tide. But then the demons and beasts showed up and started to attack him. When he questioned the Demon King, is showed that he was under mind control - most likely just like all the other demons and beasts.
Considering the speech bubble, I assume that it's implying that the angels/wingdims? are the ones behind the Earth invasion. That all those monsters that have been shown until now are under their spell. And the stone-angel-thing, that created the system that allowed our MC to get where he is, is trying to fight against them.
Oh! And Sung Jinwoo ended up in the Shadow Monarch's place because he is his successor.
I'm currently wondering wether you're trying to troll the non-novel readers or you're truly interpreting the current chapter. Everything you said is so close yet so far off the mark, I had to wonder if you had read the novel and just remembering things differently.
And nahh. The wingdings thing is refering to that weird font you can found in Microsoft Office (at least there is where I often saw em). When the wingdings is in the speech bubble, the characters (Osborne and Baram) are supposedly speaking in a language that Jin woo couldn't understand.
Just guessing from what we've seen so far in the manhwa.