Duat (pronounced "do-aht") (also Tuat and Tuaut or Akert, Amenthes, Amenti, or Neter-khertet) was the realm of the dead in ancient Egyptian mythology. The deity Osiris was believed to be the lord of the underworld since he personified rebirth and life after death, being the first mummy as depicted in the Osiris Myth.The underworld was also the residence of various other gods along with Osiris. The Duat was the region through which the sun god Re traveled from west to east each night, and it was where he battled Apep, who embodied the primordial chaos which the sun had to defeat in order to rise each morning and bring order back to the earth. It was also the place where people's souls went after death for judgement, though that was not the full extent of the afterlife. Burial chambers formed touching-points between the mundane world and the Duat, and the akh, the effectiveness of the dead, could use tombs to travel back and forth from the Duat.
Each night through the Duat the sun god Re travelled, signifying revivification as the main goal of the dead. Ra, travelled under the Earth upon his Atet barge from west to east and was transformed from its aged Atum form into Khepri, the new dawning Sun.The dead king, worshiped as a god, was also central to the mythology surrounding the concept of Duat, often depicted as being one with Re. Along with the sun god the dead king had to travel through the Kingdom of Osiris, the Duat, using the special knowledge he was supposed to possess, which was recorded in the Coffin Texts, that served as a guide to the hereafter not just for the king but for all deceased. According to the Book of Amduat, the underworld consists of twelve regions signifying the twelve hours of the sun god's journey through it, battling Apep in order to bring order back to the earth in the morning; as his rays illuminated the Duat throughout the journey, they revived the dead who occupied the underworld and let them enjoy life after death in that hour of the night when they were in the presence of the the sun god, after which they went back to their sleep waiting for the god’s return the following night.