Nae Tennouji

Nae Tennouji (天王寺 綯, Tennōji Nae) is a side character and minor antagonist in Steins;Gate who also appears as a side character in Robotics;Notes and Robotics;Notes DaSH. She is the only daughter of Yugo Tennouji and Tsuzuri Imamiya and lives in fear of Rintaro Okabe's Hououin Kyouma persona.

Personality
Nae is a very timid and reserved girl who prefers to keep out of Rintaro Okabe's way as his Hououin Kyouma persona frightens her. She is shown to not like him very much, calling him a weirdo due to his tendency to give people nicknames, and especially dislikes him calling her father "Mister Braun". She is good friends with Mayuri Shiina and Suzuha Amane though and thinks of them as her older sisters, often exchanging a friendly "Tutturu" with Mayuri, and hanging around with Suzuha when she is working in the CRT TV store.

She loves her father very much and often feels like she is imposing on him, even going so far as to learn cookery from Mayuri and Kurisu for his sake. She is deeply depressed following his suicide, though she blames Okabe and Moeka Kiryu for his death and kills the latter before wounding the former (see Plot, Vengeful Nae).

She also has an alternate personality that she calls Sergeant Clean. This personality is very strict and commanding like a military officer which she uses to force her "subordinates" to clean up rooms. While acting out this personality, she calls her "subordinates" various cutesy nicknames such as "Mister Smileybear" for Itaru Hashida. This personality was likely inspired by her father Yugo Tennouji's way of forcing others to clean, as seen in the Steins;Gate 0 Drama CD Runaway of the Free Particles.

Mayuri's Killer, Nae
In an unspecified Alpha World Line, Okabe and Mayuri attempt to flee SERN's attack by using the subways before SERN shuts them down. However, Nae follows them and attempts to hug Mayuri after catching up to her on the platform. However, she trips, leading to her accidently pushing Mayuri in front of a speeding train and killing her. Nae is traumatized by this event and it is unknown what happens to her.

Vengeful Nae
In World Line Divergence 0.523307% in the visual novel, Kurisu noticed Nae running away after her father's suicide, which implied that Nae had witnessed the event. Okabe, Kurisu and Moeka went to the latter's apartment to cancel the next D-Mail, but before Okabe could send it, Nae showed up at the apartment to kill Moeka and warn Okabe that she would kill him in 15 years. If the player chose to delay the D-Mail, Okabe decides to time-leap to before his confrontation with Yugo, and he instead stages it so that he can chase Nae and interrogate her about her cryptic warning. As Okabe realizes that Nae had time-leaped from 2025, she stabs him in his elbow and gradually jabs fingers in his wound during their conversation.

Traumatized by her father's suicide, she blamed the incident on Moeka for not stopping Yugo, and Okabe for, essentially, finding the IBN in this world-line. She joined the Rounders at some point in time, and brutally tortured and killed Okabe in 2025. Using the Future Gadget Lab's time-leap machine that SERN had locked up for 15 years, she time leaped over 2000 times, possibly double, to reach 2010 and exact her revenge against those who "killed daddy".

When Okabe asks how she will re-live the next 15 years, Nae tells him that "There's nothing for me there...", then proceeds to search for Moeka. Okabe later speculates that she would simply repeat her time-leaping and act of vengeance until she would lose sight of why she was time-leaping in the first place.

It is notable that the anime shows a different set of events for the same world line. Yugo takes Okabe, Moeka and Kurisu to an empty construction lot, so Nae does not directly witness her father's suicide and presumably does not go down a similar path of vengeance like in the visual novel.

The short manga side story Steins;Gate Rebellion of the Missing Ring - Worldline 0.000000 also depicts vengeful Nae in 2025 in the worldline at 0% divergence.

Trivia

 * In Robotics;Notes, which lies in the same universe as Steins;Gate, Nae returns as a 20-year-old employee at JAXA.

Etymology

 * The name Nae means "bind, twist, make rope" (綯).
 * Nae's surname Tennouji means "heaven/heavenly, sky, imperial" (天) (ten), "king, prince, monarch, sovereign, potentate" (王) (nou) and "temple" (寺) (ji).