Joutoku Kawahara  

, 河原 浄徳

The character you're referring to is known as Jotoku. She serves as the head monk of the temple that Ikkou lives in and his grandmother. Additionally, she acts as an assistant principal at the high school where Ikkou attends. While she may be strict with Ikkou, it's primarily because she believes he lacks discipline and doesn't work hard enough to achieve enlightenment. In the early part of the series, Jotoku has occasionally overlooked minor infractions or awakenings, but by the end of season two, she seems more aware of her strictness and its consequences. She is firm with both Ikkou and the other nuns, though Ikkou often faces punishment for his actions. Despite striking him repeatedly without remorse, Jotoku uses a staff instead of fists like others do. It's also worth noting that in her youth, Jotoku was considered beautiful by many, including herself. While we don't see much of her young appearance, she has long hair and seems taller than average, likely due to the gag.