Tenken is the manifested spirit of Sajin Komamura's Zanpakut� that is seen during the anime-exclusive Zanpakut� Rebellion and the subsequent T�jū Campaign. Despite his mighty and intimidating appearance, he appears to be a very calm individual, having yet to lose his cool. According to Gonry�maru, Tenken seems to be incredibly shy, like his Shinigami wielder, which explains why he doesn't normally talk. So far, he has only spoken once, saying the word Bankai in a deep echoing voice. (Source: Bleach Wiki)