ok so huge ass spoilers ahead
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so we've seen Duchess Ferhi (Pavel's childhood friend) hint that sion's original wish might not be what he expects it to be and well later on it will turn out to be true as sion's wish after seeing Pavel die right in front of him was to "sion" to never exist bc he believed that he was the reason everyone close to him dies, and that's why in this time-line we saw that even after searching for a long time Pavel wasn't able to find sion
it's so fucking sad sion my bby
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it's a happy ending dw ^^ (it was so good chefs kiss)

Parvel needs to stop with this wanting to die and sacrificing bs. Heck, I overthink too much that the last night after I reread this manhwa again, I even had a dream (a nightmare) of them.
There, Sion already has his last life memories fully restored, so he got super depressed after parvel died and made a wish to God to create a world without him because he felt like his existence has only ever killed the one he loves. It ended up with Parvel going back to the time he first got his stigmata, waking up while crying, while he didn't know what he is crying for, as the existence of "sion" has disappeared even from his memories. He felt like something was missing but he didn't know what it is and kept crying because his heart hurts so bad. AND THE DREAM ENDED LIKE THAT.
Please author I know you're better than that shitty dream of mine I'm kinda scared