The Gravemind has an obscure and complex personality. When he was first seen by John-117 and the Arbiter, he was calm and collected, if not seemingly sad or mournful, and he spoke with a sullen tone in his voice. He was also quite logical, psychologically analyzing the duo, and trying to convince the Arbiter of the Halo Rings true purpose, to which the Arbiter reacted with stubborn pride. The Gravemind showed no irritation to this nor the bickering of 2401 Penitent Tangent and the former Prophet of Regret. Later, though, the Gravemind showed a more emotional side, basking in his victory at High Charity, and displaying a sinister air of anger when demanding answers from the newly captured Cortana.

 

The mostly collected and impassive tone that is frequently heard from it can be justified by his implied near omniscience; his knowledge of the present and ability to accurately predict the future means that he has little reason to worry about anything. He only becomes truly irritated or angry when an unforeseen event happens, or when there is something he doesn't know. Triggers for his anger include Cortana's secrets and John's ability to rescue her. When defeated, he shows sadness, not anger; it may be that he has become used to omniscience, and is only truly angered when he is wrong. This is supported by the fact that in the level Cortana, his tone quickly changed to confidence and almost amusement when he realized parts of John-117's objective (with phrases such as "Of course, you came for her! We exist together now. Two corpses in one grave").

 

The Gravemind is not violent when it doesn't benefit him; this is what makes a Gravemind a key stage in Flood evolution. Unlike the savage and single-mindedly bloodthirsty Combat and Pure Forms that precede and obey him, the Gravemind is able to analyze situations and avoid confrontation when it is necessary for the Flood's continued survival.