fujimaru ritsuka (male) (imperial robe)
Male Ritsuka in his version of the special costume crafted by servants in Fate/Grand Order's chapter Realm of the Thanatos Impulse, Traum. It was only possible to use it during the story, it's not a Mystic Code.
For Female Ritsuka's version, see Fujimaru Ritsuka (female) (Imperial Robe).