the series is set in a the modern world where fantasy dungeon opened sometime ago similar to Solo leveling and i think that why many have have mixed feeling about the series as it so similar to solo leveling it compared to it and come out the worse for it the MC Takagi has been a dungeon explorer for two year and still stuck on the first floor hunting slimes until he kill a special slime that drops a servant card allow the holder to summon a monster or in the case of our MC a loli Valkyrie and he begins to get strongerwith her at his side.

Side note unlike Solo leveling it seem magic items and skills only work within a limited range of the dungeon entrance and the worldbuilding is a little lacking

the voice acting is ok No dubs have been made at time of review the art style not too bad similar to a lot of silver link or j.c staff series although this anime was produced by Gekkou the animation is also not bad

final thoughts if you looking for something similar to Solo leveling or Danmachi this maybe up you alley it no masterpiece but it not trash