Among those few humans whom Solovar had encountered, the one whom he called friend was Barry Allen, aka the Flash. Together, these two brought about Grodd's defeat time and time again. On one occasion, Solovar also stood next to Superman when the king's city had been revealed to the world and sought acknowledgement of their right to exist alongside them.
Although later clouding memory of their existence from humanity, Solovar revealed himself once more during the Crisis on Infinite Earths when trying to save both his world and all of the Multiverse.
When this scheme failed, Ultra had their memories erased and soon after Superman once more encounter Ultra who attempted to ensure the hero in a hallucinogenic river. Eventually, Ultra was exiled into interdimensional limbo, leaving Willie and his apes behind on terra firma.