But that's not what I'm talking about. I'm talking about the lore reason behind the glowing skull, which is a pretty big feature of the Knight, as opposed to knee-jerk reactions of punters.
Yes I understand that Promethean Knights are composed humans, but it doesn't explain why they have glowing holographic skulls.
Holographic. Glowing. LED powered by potatoes. Made of ice with a candle in it. Whatever. The technology that produces/is the skull doesn't matter.
The point is that this Promethean Knight is a weapon, and it was designed intentionally to have a head with a helmet that peels back to reveal a glowing skull underneath identical to the humans that are composed to control the knight.
tldr; The skull is pointless and non-sensical. And it's this sort of shoddy base sci-fi writing that makes Halo 4 a less tight, less hard scifi than Halo 1 was.
Because i) 343 needed them to look intimidating and b) 343 needed them to have an obvious headshot target when the shields were depleted. There's no vertical protrusion like almost all of the Covenant species have.