Thread:EvilDragonLord/@comment-26099879-20200309210559/@comment-5494183-20200310005214

Actually, only the first 20 episodes adapt the manga up to chapter 20 and something, if I don't remember wrong. From episode 21 onwards is an anime original story (with some bits that later happens in the manga).

I recommend start reading from the beginning, as the anime also changes some parts of the adapted plot.