Based on Usagi Yojimbo comic book series created by Stan Sakai.
The main character, Yuichi, describes his ancestor, Myamoto Usagi, as a Samurai. However, the title of the original comic was called Usagi Yojimbo; 'yojimbo' translates as 'bodyguard'. In both the comic and the movie Yojimbo, o Guarda-Costas (1961), which inspired it, the main character is a ronin - a wanderer and distinctive class of swordsman in the Edo period. Yuichi also leads the life of a 'masterless samurai' in the series.
The character Kitsune should raise more suspicion for the protagonists. In Japanese folklore, Kitsune are a type of yokai with magic powers, high intelligence and long-life.
The word 'Usagi', which gives the main character his family name, is often translated as rabbit. However, it is more correctly translated as 'hare' as Japan has no native species of rabbit.
Gen is a hypochondriac. A condition that makes him worry excessively about his health, even if nothing is wrong.