Renzo Shima is a carefree yet timid boy. He is also very loyal to Ryuji and Konekomaru because they grew up together in the cursed temple in Kyoto. His older brother was killed in the Blue Night. He is in love with Izumo, but is obsessed with women in general. His hair is naturally black, but dyed it pink (much to the chagrin of his father). Renzo plans to achieve the title of Meister as the Aria. He has some skills in the use of the khakkhara (錫杖|錫杖, shakujō), making him a good candidate for Meister as a Dragon.
- He hates worms.
- Renzō's pastimes and talents are smiling, lying, fake politeness and buying dirty books even if a girl is working the cash register.
- His nickname in elementary school was the "Erotic Demon".
- He is trying to be more refined now that he is in high school.
- His favorite words are, "Not suitable for print."
- He spends his days off dating girls.
- His average bath time is thirty minutes.
- His hair is brown tinged with pink; this was changed in the anime to being fully dyed pink.
- Renzō's favorite music genres are: rock, pop, R&B, hip-hop, American/European and Japanese.