From Halopedia, the Halo wiki
Not many traditional weapons work well on the Hunters. Assault Rifles and Battle Rifles only work if you can sneak behind them, but if you get close enough, melee attacks to the unarmored orange section are best, even though none of these methods are 1-hit kills. If you try to sneak behind it, be careful, because as soon as it realizes you're behind it, it will give you a good whack with its shield. Dodging a Hunter's shield swing is easy. Simply step to the side, then behind them when the Hunter begins the attack. From this position, you can proceed with melee attacks to the exposed orange back, or shoot them in the exposed area with your weapon. When the Hunter turns around to smack you, simply jump back, and bait it to charge you again. Rinse and repeat. Long range weaponry and vehicles don't work well (except for a sniper rifle shot straight to exposed flesh), because of the hunters' fuel rod cannon (Sniper Rifles or Beam Rifles don't work well otherwise in the front because of the shield for the most part). Scorpions are the exception (excluding Halo Wars) and so are most explosives. Two Fuel Rod Cannons or Rocket Launchers or one Spartan Laser to any part of the body (besides the shield) will take down a Hunter. Gravity Hammers can also be used to attack a Hunter from either the front or rear, but this is risky because it can make you an easy target for the Hunter's melee. Trying to take down a Hunter by shooting him in the back is a last resort, as Hunters travel in pairs of two, giving the second Hunter an open shot at you. Another tactic against Hunters consists of getting close to them, and when the Hunter starts to chase you to hit you with it shields, you begin to fall back, all of this while firing continually with an Assault Rifle or Battle Rifle (not firing at the shield if you can). This tactic only works in closed areas and it requires a lot of bullets to kill a Hunter (approximately 90 rounds) if you don't hit the orange zone.
Halo: Combat Evolved
A Mgalekgolo's armor is resistant to most small arms fire, and significantly reduces the damage they take from enemy projectiles (on Normal difficulty, a Hunter can still be killed with a few dozen pistol or plasma shots to the armor).
They do, however, have an exploitable weak spot which only requires a pistol shot to cause death: the exposed orange flesh located in their midsections and necks. While they keep the exposed areas on the fronts of their bodies well-covered with their shields, rarely giving the player an opening unless the Hunter tries to melee him, the creature's back has a large exposed area that is extremely vulnerable. If a rocket is fired at them, it does not matter where you are aiming, it will always kill the target with one shot (unless while playing on Legendary and sometimes Heroic mode, in which case it take as many as two rockets). Another tactic available is to shoot the green sections of their Assault cannon (only successful with the pistol).
While not on alert to an enemy's presence, they assume a stance where their neck and midsection is especially vulnerable, making for an easy 1 shot kill with a pistol or sniper.
Weapons such as the shotgun and sniper rifle work great for very short and very long distances respectively. Grenades are only moderately effective, as the Hunter could withstand a half-dozen grenade blasts. Plasma weapons (with the exception of the plasma rifle on lower difficulties) are generally ineffective, as is the needler. The MA5B Assault Rifle also typically takes too long to make a kill so other weapons are far more useful.
On Legendary, some players regarded Hunters as some of the most challenging enemies in the game. Inexperienced or careless players can fall victim to the Hunters' attacks, which, while easy to anticipate, are rather quick and powerful.
A unique way to kill a Hunter, is to melee it over and over again and can be done to the front of the Hunter; however, it is highly recommended to hit from behind, as it is easier for them to attack what's in front of them.
Another way to kill a hunter is to jump on the Hunter while he is doing a melee, and shoot the hunter's vulnerable back with a pistol, which would badly damage, if not kill, the hunter. However, often the range you jump would be so far that accurately shooting at the Hunter is difficult.
Hunters cannot ginger their enemies, unlike the later games. So the smart player would take advantage of that.
Hunters are, like all other enemies in Halo: Combat Evolved, extremely vulnerable to vehicle collisions. A Warthog can kill a Hunter instantly with even the slightest nudge or tap. This was due to the physics engine of the game, which could not determine the difference between a fast moving and a slow moving vehicle; hence all vehicle contact with an enemy on foot resulted in instant death. A Hunter could attempt a large leap away from the vehicle, however, which can sometimes result in the Hunter getting away temporarily. Be wary while trying this, as a Hunter's assault cannon shot can easily flip a Warthog and damage the player.
Halo: Combat Evolved Anniversary
Mgalekgolo in Halo: Anniversary are, like all gameplay assets, physically identical to those in the original game. However, when utilizing the remastered graphics, Hunters appear nearly identical to those in Halo: Reach, with the most notable change being the addition of an armor plate over the exposed stomach. It is important to remember that these changes are merely cosmetic; though the stomach appears protected, it in fact remains exposed, and players can still score a kill with a single pistol or sniper shot to the stomach.
Changes from Halo: Combat Evolved to Halo 2
The Hunters underwent a number of changes for Halo 2. For example, they will react more aggressively to the loss of their bond brother. They appear in fewer numbers, and they are for the most part tougher and more dangerous than in Halo: CE. They are also invulnerable to melee attacks, whereas in Halo: Combat Evolved, melee attacks would actually cause damage to the Hunter.
The most notable change is their new weapon: although similar to the old Fuel Rod Gun-like Assault cannon, the new Assault cannon fires a continuous beam of green incendiary gel rather than an arcing projectile. The weapon cannot fire as often, and it has a much lower velocity, making it easier to avoid. In addition, the Hunters are over 20% larger and 10% slower, making it much easier to target. Their increased strengths go towards your advantage when playing as the Arbiter; the Hunters are then powerful and durable allies. Finally, the Hunters have much more health than the previous game.
Most small arms do rather moderate damage against them, in contrast to the M6D's ability to kill them in a single shot. For example, on Normal difficulty, it takes 11 shots from the M6C Magnum Sidearm, 6 full bursts from the battle rifle, or 10 shots from the Covenant carbine to kill a Hunter. Do not use the energy sword, as it is worse than useless (it brings you to close quarters with the Hunter, where it can easily beat you down).The rocket launcher is greatly effective, as is the fuel rod cannon. While these weapons take two and three shots respectively to kill a Hunter on Legendary, they can damage one regardless of where it hits it. If lacking a sniper rifle or a heavy weapon, simply switch to the Covenant carbine or the battle rifle (BR's slightly stronger). To put one down, aim for the exposed flesh and empty your rounds. It should take around a magazine (maybe a magazine and a half on Legendary) to kill one. On Heroic and lower difficulties, sniper weapons will kill a Hunter in a single shot. However, on Legendary, not a single weapon can kill them in one hit. An SRS99C-S2 AM Sniper Rifle or beam rifle will take two shots to kill a Hunter on Legendary.
Grenades still do little damage against Hunters and it will usually take a large amount of them to take one down. However, grenades, hand held or fired from the Brute Shot, will disorient a Hunter, giving the player an opportunity to shoot at its exposed flesh. Perhaps the most effective method to defeat a Hunter would be to stick a Plasma Grenade to it and shoot it in its exposed back with a beam rifle or sniper rifle, as a plasma grenade in this fashion will make the Hunter do a 180 degree turn or freeze on the spot. Another interesting change from Halo: CE is that plasma grenades now stick to the Hunters' shields, whereas in Halo: CE they simply bounced off if not stuck elsewhere. Plasma grenades can also be used to kill a Hunter by sticking it in the back or stomach, which due to the arc of the throw, is not very difficult. This also gives the player time to shoot them with another weapon.
If an enemy gets too close, the Hunter will attempt a clumsy but dangerous melee attack with its shield, severely injuring if not killing the enemy. Once its partner is killed, the Hunter becomes much more aggressive and will chase the player, attempting to avenge its partner's death by only melee attacks.
When battling the UNSC Marines, one Hunter will engage the Marines in close combat, whilst the other will hang back and support with the Assault cannon. If one of the Hunters dies, the other will occasionally leap forward and attempt to smash an enemy with its shield. If this attack connects, the foe on the receiving end of the blow will invariably die. Generally, Hunters have a harder time taking down marines than they had in Halo: CE, but that is because the health of marines has been increased drastically (they almost have 175% more health in normal difficulty than the Halo: CE marines.)
During the last level of Halo 2, many players are relieved to find out that 2 pairs of Hunters are with them. Due to their amazing strength and size, it is logical to hide behind them and activate your camouflage to escape from being harmed (for beginners). However, on Legendary, some players go first, and take out as many Brutes as possible, so they won't have to deal with them later. Hunters also tend to get killed when fighting Brutes on Legendary.
Halo 2: Anniversary
Mgalekgolo in Halo 2: Anniversary are, like all gameplay assets, physically identical to those in the original game. However, when utilizing the remastered graphics, Hunters have a more detailed appearance, with the most notable change being the addition of an armor plate over the exposed stomach. It is important to remember that these changes are merely cosmetic; though the stomach appears protected, it in fact remains exposed much like in Halo: Combat Evolved Anniversary, and the stomach is just as vulnerable as it was in the original game.
Changes from Halo 2 to Halo 3
The most notable feature of Hunters in Halo 3 is that they work, react, and function very much as a pair. Their computer AI for the game allows the Hunters to seem very closely bonded to the other, finally creating the "bond brother" idea. In the game, they also do some things simultaneously, such as strike at an enemy behind together, which further displays their connections to each other. This "bond" is most noticeable in Halo 3, but somewhat appears in the previous two games as well.
Flexible armor plating covers their previously vulnerable “stomach” areas. All melee attacks are faster and much deadlier, and these Hunters now anticipate enemies behind it and can attack them. If a grenade is thrown at a Hunter, it can strafe-jump away from the explosion.
Their armor is now more interactive, making it possible to remove portions of the hunters armor through combat. If back plating is removed, there will be a bigger target to shoot at. When the spikes fall off, small stubs of Lekgolo are left where the spike used to be. Hunters are also able to be killed by melee attacks again, as in Halo: CE. However it seems that Hunters are more vulnerable to melee attacks in Halo 3. Their Assault cannons do slightly less damage, while it appears that grenades and explosives seem to do more damage to them compared to the other two games and can kill instantly if stuck on the back or neck on Heroic or a lower difficulty. Gravity Hammers can also do a great deal of damage if hit in the exposed part of their back. Meleeing them with a Brute Shot in the back usually blows off its covering armor plating, but hitting the unprotected part instantly kills it, and strangely sends the Hunter flying 30 feet in the air. This may be a glitch or just something Bungie mistakenly left in Halo 3 after development, this can be done with other species too. Theoretically, they could be killed from the front using a very precise slice to their neck from the Energy Sword.
The most effective weapons against them are support weapons and explosives. The Spartan Laser is the only weapon capable of scoring one shot kills on Legendary difficulty, and its accuracy makes it possibly the most useful anti-hunter weapon. It is also possible to kill a Hunter in one ram with a fast moving vehicle. The Missile Pod and Rocket Launcher can tear apart Hunters, as can dual plasma rifles if you hit them in their unprotected backs. A very effective, albeit difficult to use weapon is the energy sword, as one lunge at the unprotected back can kill it on Heroic. This is very hard to do because of the difficulty closing the distance, and the rareness of the energy sword in Halo 3's Campaign.
If a Hunter is unaware of the player or his allies, it will usually stand still. This is the perfect chance for the player to use a powerful scoped weapon such as the Sniper Rifle or an explosive weapon with slow projectiles and arc effects such as the Fuel Rod Gun, Plasma Grenade or Spike Grenade. If the player is in front of or on the side of the Hunter, he can use the explosive weapon on it, which will keep it from attacking you while you attack it. If he is on its rear, the best choice would be the scoped weapon, keeping a distance and shooting it in its exposed back. Of course, if he has the Rocket Launcher or the Spartan Laser with him, he should face the Hunter and destroy it with one shot. One way to get to a Hunters back is to have one teammate shoot the hunter in the front, (wasting ammo so use a plasma pistol, or an SMG) while the other player sneaks around the back and sticks it.
Halo 3: ODST
Changes from Halo 3 to Halo 3: ODST
Like in Halo 3, Hunters travel in pairs, but there is the odd moment when you will find a lone Hunter. This is possible in Campaign and Firefight. A pack of Hunters may consist of two regular Hunters, one blue Hunter and one gold Hunter, or two gold Hunters. Other than the color, the only difference between the blue and gold variants is the weapon they carry. Gold Hunters carry an Assault cannon similar in function to the cannon used by the Hunter in Halo: CE, but with rounds identical to fuel rod rounds in Halo 3. This means that the round will travel quickly, and with little arc, except for the gold coloration this cannon looks no different from the usual Halo 3 Assault cannon.
As in Halo 3, Hunters are most susceptible to attacks from behind, where powerful weapons such as the machine gun turret or rocket launcher will do incredible damage. Close quarters combat is now extremely dangerous because you run more slowly and can not jump as high while playing as an ODST. Sometimes, it is possible to put the Hunter into a chain of continuous melee attacks, regardless of how far away you are from it, and the trick is to get close enough to it to make it melee, then, back off and shoot its exposed area continuously, and it in turn will continuously melee. Be cautious when attempting this method, because if the Hunter lands a melee, it will do severe damage.
Combating gold Hunters is more risky at long range, because their fuel rod projectiles travel faster, can be fired quite quickly in succession, and carry massive splash damage. This makes them more formidable against vehicles. It is recommended that the player weaves in such a way that the Hunter will constantly have to adjust its aim. Fighting both a blue and gold variant at the same time is also tricky, because you have two different types of attacks to dodge. In firefight, teamwork is essential in taking down the Hunter, the ideal position being one person in front of the hunter, getting its attention, while another person positions himself behind it, with a clear shot at the exposed spots. Another good strategy when facing two Hunters, is to have one stand in front of the other. When the Hunter in the rear fires, he will injure the Hunter in front of him.
Another less well known tactic involves forcing the Hunter to jump off of the map. This can be done if you lead a hunter to an area with a bottomless pit (this only works on the maps Windward, Chasm Ten, and Alpha Site) and throw a grenade at their feet. With tough luck on, the Hunter will attempt to dodge the grenade and jump off of the floor and into the pit, killing itself. Grenade placement must be very precise, and in an area where the hunter will jump off of the map (to the side of the hunter if the hunter is right beside the pit).
It is always good to preserve Fuel Rod and Rocket Launcher ammunition in anticipation of Hunters. They will usually appear at least once during a set. These weapons are the most effective at Hunter killing, and it is possible to kill a Hunter in less than five seconds if well equipped. Before the mythic and tilt skulls are activated it is a good idea to use sticky grenades, unlike in Halo 3 firebombs have almost no effect.
Hunters always appear in pairs and occupy a strong anti-vehicle role. Armed with a Fuel Rod Gun, they can deliver heavy damage to UNSC ground vehicles. When one Hunter falls, it becomes much easier to kill the remaining one. As aforementioned, they are mainly anti-vehicle: they'll get rid of Warthogs, Cobras, Wolverines, Gremlins and early Scorpion versions pretty fast. However they're ineffective against infantry, and useless against aircraft. Can be trained inside the Hall for 250 resources, a population of 2, and have several upgrades:
Changes from Halo 3: ODST to Halo: Reach
Hunters are even more dangerous than in previous games. Their Assault cannon is similar to the one for Halo: Combat Evolved. They will rarely aim directly at the player, instead shooting at their feet, relying more on the splash damage then the actual projectile. Melee attacks by Hunters are much faster and more powerful, making them much more difficult to engage in close quarters. In addition Armor Lock is disabled if struck by a Hunter. Hunters will also use their shields more efficiently than in previous games. They will often use their shield to protect their exposed midsection and necks when attacked, making attacks on the back section the only viable option to kill them. However attacks on their backs are difficult to accomplish if detected by the Hunter due to their high speed. Their increased health makes successful attacks on their back less damaging. They display much greater resistance to most forms of damage, capable of surviving rockets and Spartan Laser hits head-on on Heroic difficulty and higher. They are encountered rarely, but they are extremely dangerous on any difficulty. Furthermore, with Reach's revamped physics system, splattering them is near impossible, unlike in previous games.
Changes from Halo: Reach to Halo 4
Halo 5: Guardians
Changes from Halo 4 to Halo 5: Guardians
Hunters are first encountered in Blue Team, as soon as the Spartans of Blue Team enter the laboratory. They then appear in most subsequent levels featuring Covenant enemies, and a lone Hunter can even be found in Swords of Sanghelios.
Halo Wars 2
Hunters can be built at the Raid Camp by every Banished leader, and are once again anti-vehicle units. Hunters perform well against vehicles, okay against structures, poorly against infantry, and cannot attack aircraft. Once the Beam Cannon upgrade has been researched Hunters will perform okay against infantry. In Blitz Hunters cost 40 energy while Ironclad Hunters cost 60 energy and Scarred Hunters cost 100 energy.
Goliaths are exclusive to the Banished leader "Colony" and can be built at the Raid Camp as a replacement for the Jump Pack Jiralhanae. Unupgraded Goliaths perform well against structures, okay against infantry, poorly against vehicles, and cannot attack aircraft. Once the Goliath's Rage upgrade has been researched Goliaths will perform well against infantry and okay against vehicles. In Blitz Goliaths cost 50 energy. During Operation: SPEARBREAKER, Goliaths can heal the Hunter Captain.