hmm

Sorry accidentally disliker

Dunno but my guess is he didn't get the life teaching he got now
That or he was just the biggest idiot who couldn't hold his damn temper

the big difference was his upbringing: in his past life he was only taught about life and hierarchies by other jin (as explained before where they told u about how they are separated from their parents and raised in camps etc.) since he was soon seen as the emperor because of his extreme powers he was probably taught from a young age that everyone should bow to him and that he can basically do whatever he wants since he is the strongest person on the planet... honestly tell me how is he supposed to react "nicely" when he was never told or taught differently???? But now the difference is that in this "second" life he had the uke who - without knowing he was the emperor - actually taught him about life, and what humans have to suffer and the differences in powers. he taught him ll the things about decency, appreciating others, basic manners and not to take anything for granted. To work hard and be thankful. all the things he would normally not have been taught. So now he knows to be thankful, grateful and value things differently. Of course his basic character traits are still the same as in being always over the top and focusing real hard on something/ giving 100% in that thing. In his previous life that meant he went over the top with his bad intentions and traits> treating everyone like absolute shit and just trampling on everything. Now tho it turned into an overprotectiveness over the uke stemming from fear and insecurities about their connection to each other, their relationship, and the dangers human's face that he now has been taught about by the uke.