
I can try to summarize but since chapters release slowly you're not really missing much. Leon and the demons live in a dead realm. A realm forgotten by everyone, nothing grows here, there is no prosperity here (they can also realm hop, only specific demons) and Leon who once used to be top dog begins losing his powers. The demons seeing this then realize he's no longer strong and can be pushed around, they assault him, rape him, treat him like he's their toy, and its all so that they can create life in their realm for the first time. The demons realize Leon has a womb, and the leader of the demon group (Leon's ex-butler guy) doesn't care who rapes Leon, as long as their able to impregnate him. As they continue their assaults Leon realizes how fragile his mana has become (he explains that it's like a vase full of cracks) he absorbs magic when they frick, but because there are so many cracks he can't hold the magic for a long time. Throughout this time he's wondering how to contain his magic and where is cliff. He doesn't give the womb much thought and considers the demons dumb. The other demons though are kinda shocked and concerned as to why Leon hasn't gotten pregnant yet, after all the rape he should be right? Well no, Leon's womb is rejecting their seed (I can't believe I'm writing this, the plots so bad I'm crying ヾ(❀╹◡╹)ノ~ I love Leon tho) and Mephisto (don't know his motivs) kinda helps him out? In like a weird way, he tells him the solutions to his questions by the end of season 2. We don't know exactly what mephisto told him but Leon finds a way to regain his power and through flashback we begin understanding where Leon and cliff came from. Now here's where we get to the side stories :
Cliff met Leon when he was a kid, feeling bad for Leon he gave him half his life force to keep him alive. Like cliff, Leon was sent by someone unown entity to the dead realm (cliff was framed by some evil God and sent down there) once Leon woke up, cliff began training Leon so he'd have a better chance at survival but Leon (now an adult) begins catching feelings for cliff. Cliff rejects Leon at first because Clif himself knows he's dying and that starting anything with Leon would be pointless. But Leon is able to convince him that he ain't dead yet and to just enjoy what they have now, be in the present and not think about the future type shizz. Leon's agrees and the two get
together only for the evil God to separate them (╯°Д °)╯╧╧ cliff (we don't know if he was kidnapped or agreed to go, which is highly unlikely cause if they live in a dead realm I'm pretty sure cliff would've taken Leon with him so imma say kidnapped) was kidnapped and Leon was left alone confused and scared, wondering where cliff is? He begins bearing up all the demons with his crazy powers and the demons fear, hate, admire him. But all that fighting was to find cliff. He becomes the so called demon ruler and makes a black outfit to remember cliff by, because he still wishes to find him and still wants to know what happened to him. Leon hasn't forgotten cliff. And that's where we're at with the story, the story (manhwa) begins when Leon starts losing his magic
I'd like to add this one scene that's relevant to plot. When Leon was being assaulted they tried taking his earrings (the ones cliff gave him, theyre made out of pieces of cliff) and Leon's begs them not to take them (poor baby ╥﹏╥) thankfully they don't. The earing seem to absorbs the demons powers when they frick so Leon has a way to story power, the earring come into play at the end of season 2. The other stuff I said about the side stories wasn't released in English yet but by looking at the raws that what I can surmise. We don't know what happened to cliff, where he went, who's this evil God, what is Leon up to, who is gonna be end game? We don't know but author promised the next season to be more plot heavy so hopefully we'll get our answers. If I added anything that was wrong or if I missed something feel free to add under my comment. Can't believe I actually paid attention to the plot lol, but often I can't read the rape scenes. Also everyone theorizing! You guys make my day, the theories other readers come up with are so entertaining and cool, genuinely love em. We all want Leon x cliff to be endgame, we want them demons to suffer some type of punishment, please make an actual good story pit of this author ╥﹏╥
Hope this helps!

THANKYOU SO MUCH. I SKIP A LOT OF RAPE SCENES AND I THINK I SKIPPED A LOT OF PLOT WITH IT TOO. THIS WAS SO HELPFUL. Also idk if it's true but some people say that the (new)leader of the demons is sus and that he is related to cliff. If there is any clue in the story about this pls do tell me. Thankyou again
Can someone summarise to me wtf is going on? We were on the main story(i hate it) that suddenly ended without any plot or anything and now we are on the sides that show the past. Are we gonna get back on the main story after this or it this going to end after we know all about clif?