Seihai-kun

Seihai-kun (Grail-kun) is a parody character in Carnival Phantasm. He is a mascot-styled version of the Great Grail. He was originally part of the TMitter April Fools' Day site where he was listed as (せいはいくん, ?).

His segments in Carnival Phantasm follow characters seeking help with their problems, and Grail-kun giving them a tool like the "Friendmaker", the "Hero Creation Kit" and the "Servant Strengthening Device" in a Doraemon-like manner. Each tool is just a simple kitchen knife, and he implies that they use to solve their problems in violent manners like "show him who is boss", "you'll become a hero after killing a million people" or "you should just kill him and forge a contract with a new servant" respectively.

Episode 11 of Carnival Phantasm also features him in a pseudo-guiding role as he reveals to Lancer all the ways he has died in previous episodes and tells him that he should be careful because he is the designated clown of the series and one of these deaths might truly become fatal. Ultimately, Lancer does manage to escape every single foreseen death, only to die again in a different fashion at a place in a new route he manages to create using the Holy Grail, while Seihai-kun smugly makes cryptic statements in the background.