He fell in love with jio in his first life but jio was set up by babel to be his mortal enemy and it became his mission to "judge" the king so everytime time turns back he regains his memory. he tried so many times to save jio because she always ended up dying once she turn 20 years old but after learning the truth about her and her celestial he betrayed babel and became "the executer" and created the liberators with it sole mission to set jio free from the time loop
Its pretty long so I'll summarize it vaguely. Basically Jio was cursed to live 9 lives and she can't live past 20 years old each life and once she dies on her 9th live her soul disappears into the void. Her modern life in Korea is her last. Her celestial who is her past lover in every life decides to destroy the world tree and replant the sprout everytime she dies so that her soul won't disappear after she dies and she dies forever. By destroying the world tree which is like the world and replanting it, he is like reseting the world back again and again. Well after kiddo found out her felt like his love was really insignificant because he was just a mortal and can't do anything big for her.

Can someone give spoilers about kiddo? Like his intentions and he seemed to know jio previously and how he always recognizes her, he even seemed to know something about her celestial