Someone give a spoiler on the comments at first front.
The spoiler
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Luca is the one who return the time. He remember the past too.
I think I'm dumb, what?
You can back to front of this manhwa where we can read summary. There are comment section (below author 's other work I think). See the first comment there so you can read the spoiler :)
yeahhh, I'm now enlightened after I read those. thank uuu
Did luka get reincarnated? Maybe when he was sick? He seemed to know about the assassin and it explains he's adult like behaviour