Following the theme of characters from Shuffle! being named with allusions to plants, his given name, Rin (稟) means "salary in rice" and his surname, Tsuchimi (土見) is written with the characters for 'earth' and 'visible'.
Rin is designed by Hiro Suzuhira. Hikaru Midorikawa voice him in drama CDs of first season. (Episode Lisianthus ~Episode Primula)Tomokazu Sugita and Megumi Matsumoto voice him in the anime, while Kagura Akagi and Ryoko Tanaka voice him in Really? Really!. Jerry Jewell voices him in the English version of the anime.
Rin lost both of his parents along with Kaede's mother to a car accident when he was about still attending elementary school. Around the same time that he lost his parents, he met both Sia and Nerine separately. In both cases they were separated from their fathers, and Rin played with them until their respective fathers found them. This is why both Sia and Nerine fell in love with Rin and would later on return to the human world to enroll in his high school and fight for his love. It is not known if this was before or after his parents' death.
Rin meets Primula at an arcade when she came to see him in the human world. When the two went home there was shock & talk about where Primula would live. Rin thinks of himself as a freeloader at the Fuyou family, so he thought it really wasn't up to him if Primula lived there... but Kaede then said "as long as Rin doesn't mind" Nerine also started saying that it might be a problem... but Rin realized that Primula only came to see him, and so now Primula lives in the Fuyou family home.
Rin shows minimal initiative when dealing with girls, but he develops feelings for both Sia and Nerine quickly when they arrive and spends more and more time with them. With regards to Kaede, he thinks of her only as a childhood friend. When people comment that Kaede and him would make a good couple, Rin either waves it off or says that it is strange to think of it that way. This distance kept between them is caused in part by Kaede and Rin's dark past.
A running gag that occurs very frequently is the attack of the three "groupies", consisting of Kaede's KKK (Kito-Kito Kaede-chan also means always-always kaede), Sia's SSS (Suki-suki Sia-chan also means Love-Love Sia) and Nerine's RRR (Ran-Ran Rin-chan also means Merry-Merry Rin/Nerine). The three groups appear to be led by some anonymous man that appears in every attack on Rin while watching, and usually whimpering, in the back, berating the groupies' idiocy. The "groupies" were briefly mentioned in the original game, and were expanded upon in Really? Really!.
In the anime, his hobby is building ship miniatures, and he looks really talented in that.