Angel Beats!'s GirlsDeMo is a band which have two featured singers which is Iwasawa, and Yui. From what i have learned these two have the same voice when they sing, and what surprising is that LiSa, the singer from GirlsDeMo is also the singer of Crossing Fields, and Itsuka no Tegami, which is also an opening song from Sword Art Online. Imagine two awesome animes with one same singer! Oribe Risa! a.k.a. LiSA