An Atelier and Warriors crossover was inevitable. Hisashi Koinuma, Executive Vice President of Tecmo Koei, even teased to Siliconera that they were considering "Atelier Warriors" when we talked to him at E3.
The crossover is happening sooner than we expected with Sterkenburg Cranach aka "Sterk" from Atelier Rorona (and the two other games in the Rorona trilogy) joining Warrior Orochi 3 Ultimate.
Warriors Orochi 3 Ultimate also has characters from Dead or Alive, Ninja Gaiden, Bladestorm, Warriors: Legends of Troy, Trinity: Souls of Zill O’ll, and of course Dynasty Warriors and Samurai Warriors. The Tecmo Koei family reunion comes out on PlayStation 3 and PlayStation Vita on September 26.