Ishikari-sensei is a secondary character in the anime Yumeria, serving as the homeroom teacher for the first-year class attended by the protagonist Tomokazu Mikuri and his friends. He is characterized by a very particular and contradictory nature in his interactions with students. On the surface, he presents himself as kind and accommodating to most members of the class. This general demeanor, however, stands in stark contrast to his specific treatment of Tomokazu, against whom he openly holds a grudge, making him a distinctly unsympathetic figure in the student's daily life.

Beyond this targeted animosity, Ishikari-sensei is defined by a more unusual and comedic personality trait. He is depicted as having a lolita fetish, a preference he does not attempt to hide or feel shame about, as he openly admits to it. This aspect of his character is played for humor and further establishes him as an eccentric and less-than-traditional authority figure. Physically, he appears as an adult male with short brown hair that reaches his neck and brown eyes, and his typical attire consists of a suit and tie, fitting his role as a teacher.

His role in the narrative is primarily that of a supporting character who provides a source of conflict and comedy in the real-world segments of the story, rather than being directly involved in the dream world battles. His key relationship is defined by his antagonistic dynamic with Tomokazu, which is a recurring obstacle for the protagonist in his everyday school life. There is no information available regarding any significant character development arc for Ishikari-sensei, nor are any notable abilities or unique powers detailed within the context of the anime's plot.