This is what High Guardian Spice should've been.

On the land of Naral Island, an endless battle rages between the demom lord and the Hero's party led by Yulia, for generations an endless death and rebirth has seen the battle repeat for the last 998 generations, after a spell goes wrong, the 999th reincarnation sees the Demon Lord reincarnate at a point in time before the Hero's party started at the Academy, with generations of knowledge under her belt, Demon Lord Mao decides to teach the Hero's party adventuring to avoid the fate of being slain for the final time; the latest reincarnation of the heroes are far from perfect themselves backed by an obsessed princess.
Endro, short for End Roll, a term used for ending a video game, showcases four cute girls with a cute teacher and a ditzy princess, it's traditional cute anime that never takes itself very seriously, twelve episodes is just enough for the characters not to out stay their welcome although the princess Rona can be a bit much, an anime with such cute characters doesn't warrant a good dub so it's best viewed as a sub.
This is what High Guardian Spice should've been, a clean cute story of cute characters doing cute things, there's not much to work with but it never needed it, the characters are all charming enough to drive the paper thin narrative and still be fun.
Final Verdict: A silly cute story of amateur adventurers in a world that never takes itself too seriously, what it lacks in plot it makes up in character.