The first is known as the Energy Vessel (エネルギー体, Enerugī-tai), and is the Ōtsutsuki clan's greatest treasure. This is the altar into which the Ōtsutsuki Clan had been sealing their eyes for a thousand years, and "Hamura's Tenseigan" (ハムラの転生眼, Hamura no Tenseigan) is its core -- which of course indicates that Hamura had awakened the Tenseigan at some point before sealing it in the altar. The Energy Vessel apparantly uses his Tenseigan to act as a giant senjutsu chakra engine that collects and amplifies natural energy, and the Ōtsutsuki clan used the Vessel as an energy source to power everything on the moon, including the countless autonomous puppets that served them.