Despite growing up with older orphans like Marco and Ai, Ta-kun seems to be younger than them, being around the age of both Yukiteru Amano and Yuno Gasai or perhaps just a bit older than them. Like most of the orphans, he wears a white trench coat, along with a pair of black-framed sports googles with yellow-brownish lenses. He also has long, dark brown hair.
Like most orphans under Kamado's wing, Taro loves her greatly, feeling indebted to her for raising him like her own son. For this reason, he will do anything to ensure she becomes god, as he believes she will be more than capable of creating an ideal world. Despite willingly taking arms for the sake of Kamado, he seems to avoid exposure as much as possible. He also seems to display a certain code of honor, as he willingly accepted an alliance with Yuki and Yuno, and was terrified when he finds about their betrayal, suggesting that although he may want Kamado to be god, he does not employ dirty tactics.
Being one of the most active of the orphans, suggest that outside Ai and Marco, he's one of the oldest and to a degree, leader of the rest of the orphans. The nature of his "Copy Diary" suggests he may look up to some people more than himself.
Diary & Abilities
Like most of the orphans in Mother's Village, Ta-Kun received an Apprentice Diary from Kamado once she activated the Blog Diary. His Diary is the The Copy Diary, which can perfectly replicate the abilities of any other Future Diary as long as it synchronizes with it beforehand. As an Apprentice Diary, it relies on a signal from the Blog Diary to function, but Ta-kun will not die if it is broken.
While its copy ability makes the diary versatile, it requires a willing partner; given how exchange of data is performed between cellphones, unless the second party willingly agrees to allow a copy, he won't be able to copy any diary at all. Additionally, the Copy Diary perfectly replicates any weaknesses or limitations of the original diary, and it presumably can't copy Diaries that manifest as non-electronic devices (such as the Hyper Vision Diary or the Clairvoyance Diary).
Outside of his Diary, Ta-kun appears to be skilled in infiltration, arson and explosives. He was also seen wielding a machete with certain proficiency.
The Seventh's Battle of Love
Ta-kun spied on the Kosaka Mansion when Kamado's forces invaded the mansion to kill Yukiteru and Yuno. He later played a role in setting off the explosives in Sakurami Tower, which destroyed the tower and inadvertently killed Marco Ikusaba and Ai Mikami.
The Eleventh's Kingdom
After Kamado made an alliance with Yuki and Yuno, Ta-kun, Orin Miyashiro and around twenty other orphans ambushed the Eleventh, John Bacchus, on a mountain road. Ta-kun stood next to Kamado, monitoring both the fighting and Yukiteru, whom he feared was up to something. However, John Bacchus disables their Apprentice Diaries with a signal jammer in his car, and thus removing the powers the orphans had. At this moment, Ta-kun notices Yukiteru running away from the fight against John's forces. Ta-kun watched in horror as Yuno and Yukiteru betrayed their alliance, Yukiteru shooting the orphans with a pistol while Yuno kills Orin with her sword.
Enraged, Ta-kun fights Yuno, calling them traitors. Yuno eventually stabs Ta-kun through the chest, his final words telling Kamado to run to safety before he died.
The Final Battle
In the anime, Ta-kun and Orin stand cheerlessly in front of the orphanage to see off Kamado, who walks away arm-in-arm with John Bacchus.