Ulong Luu / Summer's Domain was created by Gurang Zhi / Solane to be one of the four Rune Pillars bordering Plumamentia - specifically, the furthermost South. It embodied, amongst other things, the concepts of creation and of expansion, and was guarded by Ulong Luu / Summer, one of the four Dragon Lords / Luuwang.

At some point during the Second Era, the Azurites murdered Ulong Luu / Summer and destroyed Summer's Domain.