The Covenant

The Thunderstorm skull gives units a "field promotion"-- units are spawned as the next higher available rank. This view shows the skull at the end of the second beam tower, looking towards the area where the Hornet aircraft are first available in this level.

Rampant for over se7en years.

Taxonomy upgrade extras: 

First I'll start with the background info on these. There are 7 terminals and all of them are located on The Ark, The Covenant, and Halo. To get the achievement for getting all the terminals you have to read through the message until the terminal says, [b] "FRAGMENT ENDS" [/b] except for two occations where it says [b] "[35:52:75:63:64] xx01-83-244.53" [/b] and the other is [b] "ALL RECORDS CEASE" [/b] The Achievement you get is "Marathon Man" and I think it gives you the security armor shoulder. The Security armor is actually just a remake of the armor the main character wears in an earlier Bungie game, "Marathon". I also here there is another terminal however I haven't bothered to look. Sorry. Anyways on to the terminals.