Ruka Rengoku (煉れん獄ごく 瑠る火か Rengoku Ruka?) was the wife of Shinjuro Rengoku, and the mother of Kyojuro Rengoku and Senjuro Rengoku. Her husband speculated that their two sons have wonderful personalities mainly because of her biological influence. As opposed to her husband Shinjuro's loud personality, Ruka is depicted as being wise, gentle and graceful. In the manga, she is seen having strong morals, teaching Kyojuro the importance of his life and the need to use his strength in order to protect.