Oji Karasuma

Karasuma Oji is Tenma's love interest, often depicted as a stonefaced eccentric. He enjoys odd habits such as dressing as a kappa during rainy days, embodying a Japanese pun on the word for raincoat. He enjoys eating curry. Although unspoken, he seems to be excellent at dodging any flying projectiles including Harima's Hurricane Kick and Tenma's arrow letters. Karasuma is secretly a famous mangaka, publishing his works under the pen name of Nijō jō(二条丈). He is in a band at school, and plays an electric guitar. He also played soccer, and recently won a cup with the national soccer team in the anime.

Although he doesn't demonstrate any feeling for Tenma (or anything else), behind his poker face he sometimes shows true concern for her in the story. He suffers from a disease that eventually erases all his memories after he goes to America. Because of this he hid his feelings for Tenma not wanting to hurt her.