The term 'Assassin Japanese' can be broken down into three crossword solutions: NINJA (5 letters), ASP (3 letters), and SLAYER (6 letters). A NINJA is a covert agent or mercenary in feudal Japan, trained in the martial arts and stealth tactics. An ASP is a type of short sword used by the NINJA. Lastly, a SLAYER is someone who kills or slays another person. All three terms are related to the Assassin Japanese, as they all refer to a type of warrior or killer from Japan.