The Egyptian god of the horizon often depicted as a double lion was Aker.
Aker personified the horizon and guarded the eastern and western horizons where the sun emerged and disappeared. Egyptian artists eventually represented him as two recumbent lions seated back-to-back, often with the horizon sign and a sun disk between them.
The paired lions embodied both directions and the passage of time. One lion was called Duaj, meaning “tomorrow,” while the other was Sefe, meaning “yesterday.” Together they expressed Aker’s role as the god who looks forward and backward, overseeing the sun’s daily movement between the visible world and the underworld.
Aker also had important funerary functions. He protected the deceased king, guarded the entrance to the next world, and helped shield the dead from dangerous serpents and other threats. His mythology is described especially clearly in the Pyramid Texts of King Teti. Earlier images could show a single recumbent lion; the familiar double-lion form became prominent from the Middle Kingdom onward.
Aker is sometimes confused with Seker, another funerary deity, but the two gods had different identities. Aker’s defining imagery is the horizon and its twin lions.