A few things of note here. First of all, in this fanfic, the MC is going to be Veldora. No, not Veldora Tempest, just Veldora. This fic will start around the same time as canon, though Veldora won't be inside Rimuru's Stomach the entire first half of the story like in canon.
Second, this is a monogamous fic with the heroine being Luminous Valentine. Yes, Veldora may have a sexual relationship before getting with Luminous, however, once they are together, there will not be any cheating for either of them. Luminous and Veldora may talk about how hot someone is and might even flirt a bit, but they're loyal to one another.
Third, this fic is mostly a response to the other fanfics on reincarnating as Veldora where the MC is a psychopath whose only goal is to have as much sex as possible and collect a Pokemon harem. I was actually inspired to write this when I started reading a fic like this and the MC decided to kill Rimuru in an incredibly painful way just because Rimuru would surpass him one day. Like wtf!?! That's so petty.
Fourth, while this may be considered a 'Nanny' fic since Veldora is going to teach Rimuru quite a bit (until he becomes a TDL) and stay with him to ensure he stays alive. This is because Veldora wants to be friends with him since Rimuru is super chill and Tempest is just objectively the best place to live in that world, however, he isn't going to do everything for him and will leave Tempest for a while during the middle of the fic. For example, the attack on Tempest is an important part of Rimuru's character development, the moment he gives up on his naivete where he fully becomes a monster in both body and mind, thus resolving himself to kill humans if needed.
Finally, this is going to be a shorter fic with a decently fast pace. I doubt it'll even get to 50 chapters with what I have planned right now.