sukuna threatens mahito

Yes, Mahito did die in the manga.

Yes, Mahito dies in the manga.

Sukuna does die in the manga. The way it happens is quite dramatic and ties in with many other elements of the story, adding depth and tension to the overall narrative.

Sukuna is a powerful and persistent presence in the manga. So far, no one has succeeded in eliminating him.

No. Ryomen Sukuna is a fictional character from Japanese mythology and modern manga/anime. He doesn't have a basis in a true historical event or person.

Nope. Ryomen Sukuna has no basis in reality. It's a product of the creative minds of the writers and illustrators who designed a captivating fictional character for the enjoyment of the audience.

Sukuna didn't manage to kill Gojo. The storylines and battles unfolded in a way that Gojo remained alive and intact in the manga.

No, Sukuna doesn't kill Gojo in the manga.

No, Sukuna doesn't kill Gojo in the manga. Their battles are intense but Gojo survives.

I'm not sure specifically as it's a fanfiction. It could potentially involve Maleficent using her dark powers to intimidate Mal who is pregnant, perhaps to gain some sort of advantage or to fulfill some dark plan. But without reading the actual fanfiction, it's hard to be certain.