Ninja Slayer From Compilation Nin
ニンジャスレイヤー フロムコンピレイシヨン 「忍」
KICS-3253 (http://vgmdb.net/album/52751)

Ninja Slayer From Compilation Satsu
ニンジャスレイヤー フロムコンピレイシヨン 「殺」
KICS-3254 (http://vgmdb.net/album/54515)



Composed by Shinichi Osawa and others.
Thanks in advance.

Found them. (https://hikarinoakariost.info/?s=Ninja+Slayer+From+Compilation)

Someone with the authority can now move this thread to the download links section.