From Halopedia, the Halo wiki
During the Battle for Zeta Halo, Glibnub operated the propaganda towers on Zeta Halo. He regularly issued taunting and demoralizing messages to the UNSC personnel scattered across the ring, while also broadcasting encouraging messages to the other Banished soldiers. These messages would often contain unverifiable statements, half-truths or outright lies. Other times, he broadcasted trivial complaints over the towers. As John-117 destroyed the towers one by one, Glibnub began pleading with the human to leave the final tower alone, since without anything to spread his propaganda, Glibnub's purpose within the Banished would be gone and his superiors would kill him.
Personality and traits
Glibnub enjoyed his position in the Banished as a propaganda officer, mainly because it kept him off the battlefield and thus safe from harm. Like many Unggoy, he was mostly concerned with self-preservation and was not above pleading with his enemies (such as begging the Master Chief not to destroy all the towers) when the Banished began losing. He also didn't always take his job seriously, as he would sometimes use the propaganda towers to make personal complaints. As Master Chief and the UNSC began retaking control of Zeta Halo from Banished forces, Glibnub's confidence began to falter, at some points broke out into hysterical crying and lamenting about his dwindling usefulness over the tower broadcasts.
Glibnub displayed a certain degree of self-awareness at times, even going so far as to occasionally break the fourth wall.
List of appearances