Yuki. Her name brings up a couple of indications. She is mostly blank though not in intelligence. More as in she is incapable of expressing her true emotions. That’s by design. She was sent to earth on a mission by her masters to spy on Haruhi. But thanks to Kyon she soon discovers something that might be described as feelings. Though she may appear stoic, she is secretively soft hearted (assuming she has one) and is prone to act on her emotions without warning. I am of course, talking about the Yuki Nagato from the anime/manga series and not her other personas in alternate realities.
With that said, she is probably the most trustworthy of the SOS Brigade. She’s willing to put herself on the line to save those who are close to her. She puts up with a lot of insanity and is able to push on as long as her emotions allow her too (sometimes as far as 15,532 days of repeating the same routine over and over again). Her personal abilities in the arts and with technology supersede anyone on planet earth. Not to mention her amazing fighting abilities. It’s for the reasons despite her lack of visual emotion that I consider her to be waifu tier and worthy on my blog.
