Sein wearing sister costume in ViVid
|Other names||Sister Sein|
|Species||Cyborg (Number #6)|
|Date of birth||Spring 0061 (activated)|
|Occupation||Underground Recon (StrikerS)|
Sister / Church Knight (post-StrikerS)
|Rank||A (body augmentation rank)|
|Japanese name||セイン |
|First app.||StrikerS (ep.12)|
|Voiced by||Kaori Mizuhashi|
Sein is one of the most cheerful, yet suspicious-looking among the Numbers. Although she showed many failures in the past, her unique IS makes Sein a valuable asset in both Jail Scaglietti's and Uno's eyes due to its completeness and independence. As she stands in the dead center of the order that the Numbers were created, she normally acts as a "bridge" between her older and younger siblings. Sein and Wendi get along pretty well because of their similar temperaments and the fact that they were tutor and pupil for a while.
In episode 24, Schach Nouera knocks Sein out.
Sein is responsible for taking care of Ixpellia at the Church HQ in ViVid. She first appears in the manga when Vivio and Nove visit Ixy in chapters 2 and 3. She is then seen again in chapter 10, when she arrives to Carnaaji "to gather fresh vegetables for the Church". However, when prompted by Megane Alpine, she admits she would like to join Nanoha and the rest in their activities and plans to organize "a little hot spring surprise". This "surprise" consists of her using her Deep Diver ability to infiltrate the hot springs and grope each of the people there until Rio Wesley enters the Adult Mode and stops her. When the bathing vacationers take offense, Sein throws a tantrum, complaining that she wanted to have some fun before going back. After Sein apologizes to Lio, Lutecia persuades the others to let her stay if she cooks for them, noting that she is quite good at it. Sein notes that she also came to get some water to use for washing Ixpellia, so that she can make her feel as though she is bathing.
As the name suggests, her IS Deep Diver allows her to swim through inorganic objects (like the ground or rocks) as if they were water. The Periscope Eye Inherent Equipment is a cybernetic apparatus in her right index finger that acts as both an extra eye and as a tool to disable electronic and magical locks.