Yuugo Tennouji (天王寺 裕吾 Tennōji Yūgo) is Rintarou Okabe's landlord and the owner of the CRT store.
He has a great passion for CRT Television and refuses to upgrade to any other type. This coupled with the fact he owns a CRT store has resulted in Rintarou nicknaming him "Mr. Braun" after the inventor of CRTs, German physicist Ferdinand Braun and the common Japanese name for CRTs, "Braun Tubes".
While appearing as a tough and menacing man and often using this demeanour to jokingly bully Rintarou, he actually has a soft spot for the lab members and cares about their well-being. His daughter Nae is his top priority and he will go to desperate lengths to ensure her safety.
Yuugo has a bad temper, and is very easily annoyed by Rintarou's mannerisms as well as his "experiments" upstairs. He regularly threatens to raise the lab's rent money should the experiments continue to disturb him, though this has never actually happened.
In the presence of both his daughter and Rintarou, he would often attempt to "protect" her from Rintarou, whom he sees as a "pervert", though he was likely joking.
Yuugo was an orphan living in Paris. He grew up living a rough life in the sewers.
After seeing a gel-i-fied human in the sewers he was residing in, he was recruited by SERN, which provided the money he needed to get out of the slums. After a while, SERN ordered him to go to Akihabara in Japan. It was here that he met Suzuha Hashida, his neighbour, and Tsuzuri Imamiya, his future wife.
Sometime prior to the first D-Mail, Tennouji recruited Moeka Kiryū into the Rounders and communicated with her under the code name "FB". It was only when Rintarou and Moeka discovered his identity that FB was revealed to be a man, as he introduced himself as a woman to Moeka, and used female phrasing. Tennouji explained that he took up the exterior and identity of the one the recruit needs the most, so as to gain their blind and absolute trust and use them to no ends.
For the first half of the story, Yuugo only appears as a mean landlord to Rintarou. However, when Moeka gets cut off from FB, Rintarou decided to work with her to track down FB, who turned out to be none other than Yuugo himself. The three had a brief conversation before Yuugo, realizing his usefulness to SERN has run out, draws a gun and commits suicide, much to Rintarou and Moeka's horror.
When 1% Divergence is obtained, Yuugo is seen running his shop, having apparently never worked for SERN in this attractor field ; but as the story of Steins;Gate Zero unfolds, Okabe confronts him and forces him to admit that he is indeed still a Rounder. However, he is viewed as an ally this time because he wishes to protect Nae from the danger she might be in after seeing the faces of shadowy attackers.
Tennouji thus protects Kagari and Suzuha by having them work at his shop, and briefly uses his interrogator skill to help Okabe out in finding out who is after the former. It is hinted that he is far more ruthless and less redeemable, as he never encountered Suzu Hashida - since Suzuha traveled back to 2010 and not 1975. How much exactly his personality differs in this regard is unknown, however.
In the anime, Yuugo shot and killed Moeka before killing himself.
Yuugo appears as a side character in Steins;Gate and most subsequent spin-offs, with the exception of Braunian Motion of Love and Hate, in which he is the main character.
- In Robotics;Notes Mr. Braun is still alive and as doting on his daughter as ever in August 2019 in the Steins Gate world line.(1)
- Yuugo's call sign of FB is the acronym for "Ferdinand Braun". Yuugo himself confirmed this shortly after Rintarou discovers his identity.
- If the cosplay addon is activated in the Steins;Gate visual novel, Yuugo's new appearance resembles the character Doraemon, albeit colored green instead of blue, and would appear as if he was bare-chested.