Rin Tsubokura

is a Shinigami and a researcher of the Shinigami Research and Development Institute.

Appearance
Rin has shoulder length brown hair, part of which is arranged into a small topknot at the front of his head, which is secured by a red tie. He has small brown eyelashes. He wears the standard Shinigami uniform underneath his lab coat.

Personality
Rin is a meek and somewhat clumsy person. He becomes worked up whenever cakes are mentioned. His fondness for sweets is so great that Hiyosu notes that he is always eating them and he often has candy stuffed in his pockets.

Bount arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

Arrancar arc
In the SRDI, Rin is sitting at his station eating sweets. A bored Hiyosu tells Rin to stop and go fetch him some tea. Just then, Rin notices the arrival of two Arrancar in Karakura Town and reports his findings to his comrades.

Much to the surprise of his colleagues, Rin volunteers for a survey in the Human World to make it easier for captains and lieutenants to release their limiters. Akon agrees to send him and gives him replacement molars which are to be given to Ikkaku Madarame. Hanatarō Yamada escorts him to the Urahara Shop where Yumichika Ayasegawa is assigned to help them. Yumichika brings them to the sites where the Arrancar had previously appeared. Outside a bakery, they encounter Heita Momoyama, an Earth-bound Plus. Rin and Hanatarō stop Yumichika from performing konsō on him, insisting that they hear what he has to say first. Rin enthusiastically agrees to Heita's request that they bake a cake for his mother. After many attempts, they make a cake good enough and present it to his mother. When she rejects the cake, Rin tries to calm Heita and looks on as Yumichika and Hanatarō fend off a Menos Grande. Afterwards, they are able to present the cake again and Heita's mother eats it. Though he stepped on them during the Menos attack, Rin put a note in the bag saying that "These molars are invisible to idiots".

During a subsequent incursion by the Arrancar in the Human World, Rin alerts his fellow researchers to the arrival of the enemy. He notes that the signal indicates that it is the Espada.

The Thousand-Year Blood War arc
When Akon is arguing with Kisuke Urahara as he tries to contact Ichigo Kurosaki, Rin notes that Akon is losing his composure. Hiyosu tells Rin to begin circulating word that Ichigo is on his way to Soul Society, which he does. When he receives a message that transmitter swords will be placed at every battlefield, Rin then sends out a message to all the Shinigami in Seireitei that Ichigo is currently heading for Soul Society. He then divulges that the Quincy are somehow unable to steal his Bankai, which was confirmed by the Research and Development Institute. When their building is attacked by Jidanbō Ikkanzaka, Rin stabs Hiyosu as the latter tries to seal off the area, commenting "why?" afterwards.

Equipment
Soul Visualization Machine: In order to buy candy in the Human World, Rin brings a device which can make any soul visible to non-spiritually aware Humans without the need for a Gigai. The machine looks organic in nature, resembling an oversized slug with a head and two tentacles. Its skin is brown with purple markings and its head and neck are covered in bandages. It has one eye in its exposed eye socket and another in its mouth. There is an aerial protrusion on the back of its head. It is capable of independent movement.

Analysis Machine: While on a mission to the Human World, Rin brings a machine which can analyse reiatsu and record patterns in it. The machine resembling an oversized slug with a head and two tentacles. Its skin is green and it has three eyes. There is a small aerial protruding from the top of its head. It makes print outs using the tips of its claws to produce writing.

Zanpakutō

 * Shikai: Not Yet Revealed
 * Bankai: Not Yet Achieved