Hmm, regarding the TL note, I would probably go with cursed sword, those tend to have the feature of taking over the mind of the user, sometimes possessing something like agency/personality/their own will and making people go berzerk, in fantasy fiction and games.
Glad the series had a good...
Last chapter was easily porn level, it was just a bit more crudely censored. In older days, some outright porn doujins would often be less explicit, actually.