殺害者
Satsugai-sha
it is pronounce sudikakio
Dragon Slayer: 屠龙者/Tú lóng zhě
There is no such thing.
Depending on what you mean it could differ. スレイヤー /su rei ya/ is a Japanese term inserted from English which can be used generally, i.e. as a proper noun or just a noun meaning killer etc.
A Latin equivalent of the English noun 'slayer' is interfector. It's a masculine gender noun. The equivalent is interfectrix if the slayer is female. Another equivalent is homicida, which may be translated as 'murderer' and 'murderess'. It's the Latin noun that's used when the victim is human.
demon in Japanese is yokai. Slayer is taijiya. So it yokai taijiya, demon can also be kappa or yasha
The translation for "man slayer" in Japanese is ไบบๆฎบใ (hitogoroshi).
saigo no enjerusureija
Slayer are a thrash metal band that rock very, very, very hard. So if you rock like Slayer, you rock very, very, very hard.
男の殺害 Otoko no satsugai
永住者の殺人者 : 'eijuusha no satsujinsha'.
slayer = ayashi (a-YAH-SHEE) or satsugaisha (sa-tsu-gaa-iSHAA). the latter is probably more appropriate, but if you wanna make it sound cool, better use the first one :)