As his casket was being closed, The Great Sage Marlin Endlight used his infinite wisdom to reincarnate himself into a "Endlessly Evolving Slime". He decides to enjoy his new slimey life, until his third daughter finds him and casts a taming spell on him! Living as a familiar to his foster daughter isn't too bad: Not only is he constantly getting hugs, but he can stealthily continue to evolve and watch over all his beloved daughters. Until he obtains a human form, he will hide his true identity from them. But let it be known that while Sura-chan (ex-Great Sage) is around, no number of greedy fake researchers, bandits or evil cults will harm his girls!
The story is boring and the FLs are described to be these unparalleled geniuses in their craft but they seem to struggle an unnatural amount with almost every task they do. Also it's high key creepy that the father figure is perverted to the daughters. There's a lot of unnecessary ecchi that honestly would make the manga a lot better if it wasn't there. I like the evolving mechanic but he doesn't really use his abilities very well and makes good abilities sorta shit.