Cthulhy Squele presides over Lindworm Central Hospital as its head. Her appearance blends human and squid-like traits, manifesting as an extremely voluptuous middle-aged woman with vibrant red hair, piercing blue eyes, and spectacles. Eight red squid tentacles form her lower body, typically extending from beneath a formal white blouse and tight dark pencil skirt.

She mentored Glenn Litbeit and Saphentite Neikes during their studies at Nemea Academy and subsequently provided crucial support for founding their Litbeit Clinic. Professionally, she tests former students by assigning unusual cases, showcasing her faith in their medical abilities. However, she exhibits overtly flirtatious and lecherous behavior, shamelessly using her tentacles to grope Glenn and Saphentite. When anxious or irritated, she habitually chews or bites her own tentacles.

Her significant responsibilities include researching monster magic and anatomy. She collaborated directly with Glenn to devise a treatment for Skadi Dragenfelt's parasitic condition, leading to a high-risk surgery. This procedure resulted in severe burns to Cthulhy's tentacles, necessitating a substantial recovery period.

As a condition of her financial backing for Glenn's clinic, Cthulhy instituted a strict "no fraternization" rule. This mandate directly fueled Glenn's reluctance to pursue romantic relationships with patients or colleagues until achieving financial independence. She reappeared in a flashback during Glenn and Saphentite's graduation ceremony.

Her name directly references H.P. Lovecraft's Cthulhu, reflecting her squid-like physiology.