Kousei Shimazaki is a supporting character in the anime Please Twins. He is a teenage high school student with short maroon hair and black eyes, and he sits next to his friend Maiku Kamishiro in class. At the start of the series, Kousei is Maiku's only close friend, and he often jokingly flirts with Maiku or makes exaggerated romantic advances toward him, which usually results in Maiku physically pushing him away or showing visible disgust. This behavior is a front, as Kousei actually harbors genuine romantic feelings for fellow student Tsubaki Oribe. He initially lacks the confidence to express these feelings directly, so he masks them with his playful, over-the-top persona. Throughout the story, Kousei wrestles with his emotions while watching Tsubaki nurse a crush on Maiku. His primary motivation is to win Tsubaki's affection and to be honest with himself and others about his love. The turning point comes during an event where another character attempts to pair Tsubaki with Maiku, causing frustration that pushes both Kousei and Tsubaki to acknowledge their true feelings. This leads Kousei to drop his pretense and openly pursue Tsubaki, marking his key development from someone who hides behind jokes and false advances into a person capable of sincere emotional expression. He has no special or supernatural abilities; his role is grounded in the everyday dynamics of friendship, unrequited love, and personal growth.