The Icerune Crater was one of several city-relics on Sapience, and it could be found on the western side of the city of Cyrene. When empowered with the corpses of Lesser Eidolons spawned from the Fonts of other cities, the Icerune Crater is able to return Blu, the Guardian Dragon of Cyrene, to the city to help protect it.
The Icerune Crater was first used in this way to return Blu to Cyrene when he was abducted by the qlippah.
The font was destroyed by Blu at the behest of the Tsol'teth invaders in the year 799AF, during an invasion to the city-state of Cyrene in the Third Black Wave.
The Icerune Crater was replaced by the Unending Spring.