NaNaNa Najahkoop is a member of the Wandenreich's Sternritter with the letter 'U'.
NaNaNa is a dark-skinned man who wears a yellow visor over the top half of his face. His hair is fashioned into five different points and he has black and white checkered teeth. He wears the traditional Sternritter hooded cloak over a small, chest long top which reveals the entirety of his abdomen. He is extremely thin and lanky and wears rings on his fingers.
NaNaNa is a crude man, asking Rojuro Ootoribashi straight out if some of his men had been killed. He doesn't believe in, nor does he understand art. He is quite arrogant, claiming he can kill Rojuro in five minutes. By Rojuro's admission, NaNaNa is quick to find faults with his comrades.
Plot - The Thousand Year Blood War Arc
NaNaNa Najahkoop is part of the initial invasion force that attacks Seireitei. He immediately confronts Captain Rojuro 'Rose' Ootoribashi, wondering if one of his men had been killed when Rose receives word of Kira's defeat. When Rose replies that he doesn't want to answer, NaNaNa insists on knowing, as if Kira is alive, it means Bazz-B has failed. He then tells Rose that he'll kill him in just five minutes and that he won't have a chance to cry. Rose rebukes him by telling him he won't leave alive, to which NaNaNa smirks in response.
NaNaNa is later seen attempting to ambush Shigekuni Genryuusai Yamamoto with Bazz-B and Äs Nödt. He comments that it was foolish of the leader to come all by himself, but is quickly incinerated. Having survived the attack thanks to Bazz-B, NaNaNa is present when Yhwach reveals Uryu Ishida to be his successor. Like his comrades, NaNaNa is shocked by the announcement.
Later, during the Wandenreich's second invasion of Soul Society, NaNaNa spies on Renji Abarai, who is sleeping in their stronghold. NaNaNa comments that he came to see who defeated Mask de Masculine, only to find Renji asleep. Thinking it was a trap, NaNaNa watched Renji until he woke up and left, surprising NaNaNa. However, NaNaNa watches him leave, commenting that he's never observed an enemy for so long and because of that, Renji is finished.