Dantas

If his memory wasn't erased why does he act like he's experiencing everything for the first time and his omniscience isn't working?

Lord of the mysteries?

l'autorité que donne la voie de l'Empereur Noir est l'autorité du désordre et non l'autorité du Chaos

Where can I read the original novel?

as he doesn't have as much mana as the "Dragon Heart", being practically "Angra Mainyu 'everyone's evil'" he should have a "Divine Core" so consequently he would have an immense amount of mana (Google translate)

and what is the strength level of the “First-class God” Realm of “Dragon Prince Yuan” compared to the others?

You know that Lucifer, Michael and Gabriel have the same level of strength in "DC Cosmology", right? Only losing to the presence and Lucifer is only "stronger" because he is the favorite and has "more" authority over the "Demiurge" Power. But other than that they have the same strength. So this chapter didn't make much sense. Although this is a story, right? And so it's not supposed to make sense, but I was a little worried about it.

You know that all the "Quincys" in Bleach have matter manipulation, right? So this ends up leaving his Shikai useless

Will he eat the fruits of the other Tree?

Sukuna is not called the king of curses in the literal sense, he is called the king of curses. Because he is the greatest "jujutsu" user that ever existed and jujutsu is a curse, understand? Witchcraft.