The Asgard were a highly established, kind race in the Ida Galaxy which saw as well as shielded people in the world and in other places. When engaging with early people, they impersonated beneficent safety gods, eventually triggering the Norse mythology in the world.
Part of the Alliance of Four Great Races, they were amongst the most innovative races in deep space, matched only by the Ancients, the Nox, and possibly the Furlings. They represented guards of the Milky Way galaxy as well as later passed that duty to the Tau‘ ri, to whom they gifted all of their understanding to.
info from: https://stargate.fandom.com/wiki/Asgard