So - Covenants for machines are literally just their form of kingdoms. There are five:

-Forge, the big bois. They have less fast vehicles or HE glory and more slow, clunky clumps of armor and lots of large, kinetic shells. Because the NightWing's volcano won't erupt anymore, they take advantage of the heat to easily mold their troops.

-Servo, the exact opposite of Forge. They have very fast soldiers and small but aerodynamic HE bullets. However, a single well-placed hit can easily kill one. They live in the Pyrrhian deserts so that they can glide along as much as they want.

-Mainframe, the smart bois. Their advantage is in advanced tech - plasma cannons and railgun artillery. However, they have very few big troops as just making their weapons takes enough time already.

-Core, the everything bois. Core is much smaller than it's fellow Covenants in numbers, but makes up for that in stubbornness. Their titan war-forms make them formidable players in the great game of life, and they have survived unknown to Queen Wasp.

-Pack, a bunch of rabid animals. Seriously. You as the player can't play as a Pack war-form because unless you are an ancient kaiju war-form you won't have any personality or intelligence, just instinct.