Shiina

Yukari's Sekirei who is searching for Kusano, whom he has a very close, sibling-like relationship with despite the fact that his power is the natural opposite of hers. His power, while not officially named, allows him to emit an energy wave that instantly disintegrate most forms of matter, including metal, wood, fabric, and even human flesh to a limited degree. He met Yukari after he was attacked and was saved by her with assistance from Homura. He shudders at the idea of almost being Mikogami's sekirei and thinks of Yukari as a bright shining light in his life. Like Kusano, Shiina dislikes violence and has expressed extreme remorse for hurting Sekirei he has defeated. Due to the overwhelming power of his ability, he is called the "Death Sekirei" and along with Yukari, are ironically considered to be the "most evil pair" in Tokyo upon reaching the Northern part of the city. Shiina and Yukari's reputation and power have become so feared that they have attracted the attention of Izumi Higa, who encountered them shortly after arriving at the North city attempting to find the last unwinged Sekirei as he (Shiina) and Yukari were hoping it would turn out to be Kusano (who, of course, already has an Ashikabi in Minato) but was later revealed to be Kagari/Homura. Higa later captured Yukari and uses her to force Shiina to work for him. His Norito is "The corpse of my covenant, rot the cross of my Ashikabi!" His name literally means "Death".

(Source: Wikipedia)