These are the units and buildings in Halowars, as stated in the UNSC and Covenant field manuals, narrow them down by category on the left navigation menu.
The Type-25 Assault Gun Carriage, also known as the Covenant Wraith is their main battle vehicle. Heaviy armored, it functions more like a tank than it’s artillery-like cannon would imply. It fires a heavy plasma blast at targets causing area of effect damage, and melting through enemy armor. The Wraith is fairly quick and can devastate enemy armor columns and infantry at range. It is also equipped with anti-personnel plasma cannons. They carry thick armor that is almost invulnerable to small-arms fire.
The Type-32 Rapid Assault Vehicle, called the Ghost by the UNSC, is a very commonly used scout vehicle by the Covenant. It is lightly armored and carries twin plasma cannons for armament. It is quick and excellent for harassing infantry and even UNSC tanks have trouble hitting it since it is so agile. Piloted by an Elite, it is very effective as a light vehicle.
The Ghost has very powerful upgrades such as a boost ability, additional thrusters allowing it to strafe and juke incoming enemy fire, and finally an energy shield that deflects incoming damage.
The Locust, like the Scarab, is another converted mining vehicle repurposed for military use. The Locust uses a powerful mining laser to inflict great damage to buildings. Although slow and expensive, the Locust is still a serious threat to UNSC forces, and buildings. It has an incredible range and can hit enemy forces when even their longest range units cannot strike back. Once upgraded, a pack of Locusts can quickly decimate an enemy base in only a few seconds.
The Factory is the manufacturing facility for Ghost scouts, Wraith Tanks and Locust walkers. This building serves as a sophisticated warehouse for all of the land based vehicles in the Covenants arsenal, and the powerful upgrades for all of the units are also researched here.
The Covenant can build the Factory immediately from the get-go without having to upgrade the Citadel giving them early land based firepower.
The Vampire is the mainstay of Covenant anti-air aircraft. With a heavy Needler turret, the Vampire can quickly overwhelm enemy air forces with a large barrage. Very effective in groups, it can bring an opposing aircraft down in seconds. When upgraded, the Vampire can drain enemy aircraft of their energy and cause it to crash to the ground, although this causes the Vampire to take damage as well.
The Engineer, known as the Huragok by the Covenant, is a race of gas-filled alien creatures created by the Forerunners to perform maintenance on Forerunner structures. The Engineers are the only way for the Covenant to repair their building and vehicles during combat and are very effective, especially once upgraded. They automatically search out damaged machinery to repair. They have no defenses or weapons and are easily killed, although they can repair each other, but not themselves.
The most frequently seen Covenant Aircraft is the Type-26 Ground Support Aircraft, or Banshee. Carrying one pilot, this versatile and nimble aircraft is used to scout and harass enemy forces. Carrying twin plasma cannons and a fuel rod cannon, the Banshee can deal serious damage to both ground and air forces. It also has been known to have a speed boost ability.
The Summit is the roost for all the the Covenants powerful air force. The quick Banshee, the deadly Vampire and the versatile Engineers are all built here. The upgrades that make the Covenant Air Force even more fierce are available here.
The Hunters, or Mgalekgolo, are massive colonies of small work-like created known as Lekgolo. These colonies of many smaller creatures take the form of huge, heavily-armored bipedal infantry. Carrying a massive shield and a Fuel Rod Gun, Hunters occupy a strong anti-vehicle role. Always appearing in pairs, they are more than a match for most UNSC Vehicles.
The Grunts, or Unggoy, are the foot soldiers of Covenant ground forces. Used in large numbers to overwhelm enemy positions, Grunts are weak as individuals but are a force to be reckoned with in groups. Almost always lead by a higher-caste Covenant infantry unit, such as a Brute or Elite, they can wield most Covenant weapons.
The methane tanks that they breath from sometimes explode with funny results.