User blog comment:Croc117/Deadly Duo:Nathan Hale & Joseph Capelli Vs. Master Chief & The Arbiter/@comment-422690-20101221202848/@comment-422690-20101221205829

Then again, the shield wear down pretty rapidly against sustained fire. Like the Wraith or the Bullseye. Something that causes organics to explode will likely wear down the shields faster. Personally, I'd've gone with the Pulse Cannon over the hands, but what can you do. In additin, their suits have proven themselves vulnerable to fire (as in, burning), and the Spider Grenade utilizes just that.

And comparing the Chimeran conquest of Earth with the Covenant's is apples to oranges. The Covenant came with a massed army, ships, and eveything already built. The Chimeran came with a few cells of a virus. They had to assimilate and build EVERYTHING from scratch.

and IIRC, isn't the Arbiter part of the Covenant?