TenSura: Time Paradox

after the final fight of rimuru, felway and ivarage the cardinal world are in state of collapse and no other living creatures are alive except for rimuru.
None of his friend, family, subordinates and even other companions are survived after that Rimuru asked ciel if they can traveled through the past and correct all of his mistakes, but theres a problem he found himself 20,000 years before his reincarnation what he will do?

Note: i do not own or owning [tensei shitara slime datta ken]

I'm not so well at english so they might have a grammatical issues but please tell me if there's a problem

character development:

-ciel new body

-ciel's Kuudere personality(this is much better than yandere)

-Matured milim heh?

-Rimuru new look

-New personality

-male rimuru

-Handsome rimuru-sama of course

-more op rimuru

-rimuru's new name

-Harem perhaps? or just flirting buddies with some girl characters
(idk why i prefer just a wholesome flirting like than a harem fucking each other)

-expect some little bit of 🍋 just a lil bit💀

-there might have a comedy but im focusing in serious mode story and rimuru is more matured than usual

A/N some of the pictures that i drop are mine and some of them are wasn't,
im just gonna put some credits below the pic if it doesn't mine.