WMG / Redo of Healer

Keyaru will be a father

He will have a LOT of children by the end of series due to his active sex-life with his harem. Likely the first child will be born from Freya.

Keyaru will die by the end

Keyaru's Redo...

will be undone by Flare who manages to regain her original personality, and wants to avenge herself for the humiliation that she's experienced in the new timeline.

Adding to the above

It will turn out that he and Flare have done or will do this dance numerous times before and after, with small leaks in the timeline allowing them to remember snippets from the previous, as well as retaining their mutual attraction

After Bullet, the next enemy Keyaru faces will be that old advisor.

The Alchemist who was beside Princess Flare and concocted a drug to addict Keyaru in the first place.

Either that, or Flare actually does have some memory of what happened.

As for why she goes along with it? She does mention briefly that what happens under the eyes of her father were relatively unpleasant.

The real reason why Anna didn't bite her tongue off in the anime.

It's because Renard happily gloats on how he's impersonating Keyaru all the while raping her.

Flare

has recovered her memories but is genuinely loyal to KeyaruThere were too many hints for her to not figure things out and unlock her memories. She's still loyal to Keyaru because by the time it happened it was clear he had improved her life, so she continues pretending.

Redo of Healer is an isekai.

Long before the events of Redo of Healer, Keyaru (now Keyarga) was an ordinary Japanese teenage boy who was ran over by a bus, killing him shortly after.