Grundig’s planet was destroyed by Galactus. He joined the Intergalactic Coalition of Survivors, a group of beings whose planet had suffered the same fate. Eventually, he became an elder of the group. They searched the universe for the Silver Surfer to pay for his crimes against them.
When the armada caught up with the Silver Surfer, it was Grundig who used his power to visually project his thoughts to the Surfer. The Surfer did not resist and Grundig found him guilty of his crimes. When the ship’s began to use their entire power supply in an attempt to kill the Surfer, he believed they should leave while they still had the power. If not, they would be stuck in the system for a very long time. It was Tinac who ordered them to keep going, which did indeed leave them stranded and the Surfer unharmed.