Series name (JP): ソウルイーター
Set in the Shinigami technical school for weapon meisters, the series revolves around 3 groups of each a weapon meister and a human weapon. Trying to make the latter a “Death Scythe” and thus fit for use by the Shinigami, they must collect the souls of 99 evil humans and 1 witch.
https://www.animenewsnetwork.com/encyclopedia/anime.php?id=9070