Mamist
Someone who advocates for Mamism, the radical belief that Mami Nanami is the best girl in the anime Kanojo, Okarishimasu (Rent-a-Girlfriend)
Person 1: "who's your top waifu from rent a girlfriend?"
Mamist: "Mami-chan"
Person 2: "What the hell?"
Mamist: "Mami-chan"
Person 2: "What the hell?"