From Halopedia, the Halo wiki
I actively run one of the largest Halo-themed iFunny accounts, TheArbiter117.
Probably something from Halo 3. A favorite of these would be during the mission Cortana. The Arbiter comes to save Chief and Cortana on High Charity. I love when she says "I've got a friendly contact! Who would be crazy enough to come in here?" And bam! There's the Arbiter being badass wielding a flamethrower. It speaks volumes toward his character development.
I hate everything about the term "hyper lethal vector."