“......... Don`t worry! No matter how bad things get, I`ll always be here! Even if you become an old spinster... I`ll stick together with you in the old folks home.”
—Tamamin to Satoko "Sugi-san" Sugiyama
Tamanin is a very pretty and cute girl with chest-length brownish hair that she often wears in two pig tail ponytails on each side of her head, and flower shaped barrettes in hair, brown eyes and she has the shortest height out of Akiko "Akko" Oohashi's friends.
Tamanin is a very cheerful girl who is usually seen with either manga or trying to cosplay at every chance, which annoys Satoko "Sugi-san" Sugiyama, seen in chapter 21.5 where she attempted to dress as Cure Dream to a mixer, or during her pool trip with Akiko "Akko" Oohashi where she made her own custom made swimsuit, which was anime based and caused her to get odd tan lines on her whole chest as a result. She is also quite airheaded at times and slow to catching on to things, such as not ever noticing that Akko and Mariko "Mari" Kumakura have feelings for each other, or by the end where she tried to get in a photo booth photo with Akko and Mari, failing to realize that the two of them were a couple and wanted a photo alone, which caused Sugiyama great surprise that Tamanin had not noticed yet. Tamanin does have a determined side to her, as since Chapter 16, as she vowed to try really hard to get a good boyfriend who shares much of the same hobbies as her during her pool and beach trips.
Tamanin is very close friends with Sugiyama despite Sugiyama`s hate of nearly everything otaku or anime based. Even though they claim not to have romantic feelings for each other they share a very close physical relationship and often kiss one another and make out especially when they are drunk, at one point in her talk with Akiko "Akko" Oohashi, Sugiyama says that her and Tamanin have kissed atleast a hundred times already. Tamanin is also the only one who is seen hanging around with Sugiyama the most and the two are often seen together often going to events such as mixers etc. with her all the time and at one point says that even when they are old and wrinkled she will still remain Sugiyama's friend. Tamanin also understands Sugiyama the most and is supportive of her relationship problems and tries to give her good advice on finding and choosing the one boyfriend out of her five she actually likes the most.
Tamanin first meets Harada after Mariko "Mari" Kumakura breaks up with him and she is seen briefly flirting with him and asking him many questions along with Sugiyama. Later, it is highly implied that the two are dating as seen in a photo of the two together cosplaying as Vocaloid characters at the end of the manga.
The two do not interact much at all but it is revealed during Chapter 14.5 that Tamanin has drawn pictures of Naru naked and puts her in 18+ rated dojin rape manga and post them on an adult website which upon finding out has caused Naru to feel uneasiness everytime she is in Tamanin's presence.
- The name Tamami means "bead" (珠) (tama) and "fruit, good result, truth" (実) (mi).
- Tamami's surname Sekine means "connection, barrier, gateway, involve, concerning" (関) (seki) and "root" (根) (ne).
- Tamanin is an otaku
- Tamanin enjoys reading manga and cosplaying