: I feel like this has been explained better elsewhere, but here's my
: understanding: Regret's fleet discovered the location of the portal to the
: Ark, so he brought his small personal fleet with him, not expecting it to
: be the humans homeworld. Truth, on the other hand, had already discovered
: Earths' location through other means (yet to be explained), and was
: amassing the largest fleet ever, composed entirely of his loyal Brutes.
: This fleet was largely destroyed at Unyielding Hierophant. What was left
: was the ships we see in ODST.

: Truth was keeping this secret, at least from Regret, definitely from the
: council as a whole. I'd love to see the terminals explore this better.

It seems like they will, but the Unyielding Hierophant was also a mixed fleet of both Brutes and Elites, or predominantly elites. Then again, the original plans for H2 seem to not have had the Brutes be Elite replacements, and rather be a new recently added species to the Covenant as First Strike suggested. Which was then retconned by Contact Harvest and Halo Wars.