GruntsGrunts are the cannon fodder of the Covenant. They are on Halo in great numbers; partially for comic relief, partially to give you something to test new weapons on. There are, of course, a few situations where they are actually dangerous, like when they are sticking plasma grenades to your forehead, or when they are accompanied by more powerful creatures.
Unfortunately, you cannot completely ignore Grunts, as they are sometimes well armed, and the damage they do can build up quickly when they come at you in large numbers. For this reason (plus the fact that they are very quick to kill), it is often a good idea to take out the Grunts before attacking their larger friends.
The easiest way to kill Grunts is well, just shoot them. Shoot them with anything and they will go down in a few shots. Ammunition-limited weapons like the rocket launcher or sniper rifle are probably overkill unless you have ammo to burn. Grenades work especially well on them when they are in large groups.
Grunts are divided into three subtypes:
These glorious fellows are on the bottom rung of the Covenant ladder. Armed with either a needler or a plasma pistol (and the occasional grenade), these guys are more likely to run than fight. When they do fight, the chance of them hitting anything is slim.
Red Grunts are armed in the same manner as their Yellow relatives. The only real difference is that they are slightly better shots, and don't run away quite as much.
These are the only Grunts that actually represent a serious threat to your safety. They can sometimes hit what they aim at, and often don't run away at all. In addition to the weaponry issued to lesser Grunts, they sometimes have plasma rifles or fuel rod guns. They make better use of grenades, and can actually present a challenge.
JackalsJackals are fairly weak Covenant troops, armed with plasma pistols and hand-held energy shields. Jackals aren't all that particularly tough or strong, but their energy shields can really make them a pain. When their shields are up, they are protected from most incoming fire, but are still able to fire out through a small slit in the shield.
Their weapon doesn't do that much damage (except for the occasional charged burst that can completely drain your shields), but Jackals are great for tying you up while their comrades dish out the damage.
The best way to deal with Jackals is from a distance with an accurate weapon like the pistol or the sniper rifle. With their shields down, a quick shot or two will take them out; if their shields are up, you can fire through the tiny slit in the side of their shield. This either kills them outright or causes them to stagger, giving you a clean shot at their body.
If you have plenty of time and don't want to waste a grenade, you can take them down by firing full force into their shields while strafing around their weapon side. You will either move far enough to get access to their bodies, or will unbalance them, causing them to roll and give you a chance at a killing shot.
Jackals come in two types:
Blue Jackals are the lesser of the two types. They are armed with a plasma pistol and with the hand-held energy shield.
Yellow Jackals are essentially identical to the Blue variety, save that they are just a bit more accurate with their weaponry and a bit harder to knock off balance.