Halo Wars 2 skulls

The Skull section of the main menu in Halo Wars 2.

Skulls are game modifiers featured in Halo Wars 2. When unlocked and activated they can alter gameplay difficulty and add interesting features.

There are fifteen skulls in total and they are awarded for completing specific Primary Objectives, Optional Objectives, or unmarked tasks throughout all of the missions in the game's campaign with the exception of the game's prologue The Signal and the DLC campaigns Operation: SPEARBREAKER and Awakening the Nightmare.

List of skulls

Grunt Birthday Party

"Killed Grunts explode into a shower of confetti, bringing joy to the battlefield - if you're not a Grunt, that is."

Unlock requirement: Capture four of Decimus' Power Nodes on the level A New Enemy.
Notes: After building your base, four Power Nodes will be shown around the map, indicated by an energy bolt icon. Move your infantry units to each of the nodes to capture them. Make sure to do this before carrying on with the Primary Objective.

Paintball

"Marine grenades and Grunt mines splatter the environment with color (as well as deadly shrapnel). Time to paint the town!"

Unlock requirement: Destroy the Banished base on Ascension.
Notes: After building your base, begin building a large army of Hornets and Cyclopes. Once you're set, head north, beyond Capture Node B, and you will find the Banished base. Do not capture any of the Capture Nodes until after destroying the base (so you won't face any opposition later). It is best to set up quickly, before the Banished can make its first move to capture a Node.

Pain Train

"All player units train 50% faster."

Unlock requirement: Destroy the hidden facility's four structures on Ascension.
Notes: After building your base, take three or four Hornets and move them to the darkened island south of your base. Here, you will find a hidden Banished base with a few Infantry Units. Use your Hornets to destroy the enemies and the four structures of the base.

Bountiful Harvest

"Supplies from supply buildings arrive 25% faster."

Unlock requirement: Don't let any of the four prison squads die on One Three Zero.
Notes: During this mission, Alice will be required to rescue four squads of prisoners, the first half of which are Hellbringers and the second half of which are Warthog Units and Cyclopses. Try to keep the Hellbringers in the rear while you focus on controlling/moving Alice throughout the mission. Once your entire squadron reaches the comms building, move your Hellbringers and Warthogs behind the building. Now move Alice and one Cyclops into one of the two garrisons in front of the building and move the other two Cyclops into the other garrison. Hold out like this until extraction arrives, making sure none of the Cyclops or Units behind the building die. It is okay to lose a few units, but do not lose a whole squad.

Emperor

"All player powers recharge in half the time."

Unlock requirement: Destroy both minibases in the central chamber on The Cartographer.
Notes: After powering down and passing through the energy barrier, you may notice that in the northern end of the chamber, on both the eastern and western edges, are Banished minibases. Make sure to destroy both bases before moving on with the Primary Objective.

Pestilence

"All player units slowly lose health from the moment they're built."

Unlock requirement: Release all 10 UNSC Prisoners on Lights Out.
Notes: You will find your first set of prisoners just north of the mission start or after the reunion with Douglas-042. Then, after passing through the portal, you will need to head to the right-hand side of the valley to find three additional cells of prisoners. Make sure to rescue them before fighting Decimus.

Total Annihilation

"Spartan special ability slams create an even more powerful explosion upon landing."

Unlock requirement: Complete the entirety of From the Deep without Spartan Alice being downed.
Notes: The best method to employ for this task is to have Alice either hijack a Wraith on the beach or take control of the Scorpion tank on the beach (either works). Make sure Alice is your primary focus throughout the mission; heal her when needed and make sure she doesn't take the brunt of the enemy's attacks. When the Scarab shows up at the end of the mission, you should already have a sizable army of Anti-Tanks (Cyclops and Scorpions) to accompany Alice in taking it down quickly. It's better to have a Nightingale accompany Alice most of the time, to save resources from using Restoration Drones. In addition, you can also do it in conjunction with hijacking a Locust as part of the Bonus Objective and it has more range to allow Alice to build up veterancy without taking too many hits.

Sickness

"All player units have 50% fewer hit points."

Unlock requirement: Keep the barricades intact on Hold the Line.
Notes: In this mission, you will need to protect the western and eastern barricades; the former of which is just to the left of your base and the latter of which is a little southeast of your base. The best way to ensure they aren't overwhelmed and destroyed is to build one Anti-Infantry and one Anti-Vehicle turret at each barricade and then place at least three or four Hornets and one Nightingale just ahead of the barricade as the "first line of defense." It's recommended to try doing this on a low difficulty, as the enemy forces become increasingly difficult to keep at bay past the fifteen minute mark. Alternately, create a kill zone with mixed anti-tanks and infantries (Recommended group of Full Upgrade Marines, Cyclops, and Nightingales) for better efficiency. In addition, two siege turrets and two anti-air turrets should be built on the base for defense support.

Firestarter

"Grunts and Marines explode on death inflicting damage on enemy units."

Unlock requirement: Keep the particle cannon above 50% health on Hold the Line.
Notes: If you are successful in keeping both barricades intact for the Sickness skull, then you shouldn't have to worry about this because no enemy Units would have been able to reach the Particle Cannon.

Things That Go Boom

"Hero units unleash a nuclear explosion on death."

Unlock requirement: Eliminate all three Brute Warlords on Under the Dark.
Notes: You will come into contact with the first Warlord by moving your Units past the first base you build and down the ridge to the Banished's base during Jerome-092 and Allieri's segment. Provided you stick to the right-hand side of the valley/map once you are in Alice's segment of the mission, you will encounter the second Warlord on your way to the first Kodiak deployment position. The last Warlord can be confronted by continuing to travel north on this eastern edge of the valley; once you reach the second red energy barrier, he will attack you. While the Warlords have a large amount of health, Snipers can do the job best since they can take out the Warlords without taking any hits and from long distances.

Wuv Woo

"Scarab and Locust beam weapons shoot rainbows made of pure love and hearts. Maybe Atriox isn't such a bad guy after all!"

Unlock requirement: Keep The Scarab alive throughout the entire level on The Foundry.
Notes: Keeping the Scarab alive through the mission shouldn't be too much of an issue if you're playing on one of the lower difficulties. If you're playing on Heroic or Legendary, though, make sure the Scarab stays at the rear of your squad so it doesn't take too much damage. Move slowly at all times and be smart as to when it's necessary to retreat and heal your Units. Always bring Nightingales to keep the Scarab constantly healed at all times. Have a mix of Kodiaks, Snipers, and Wolverines for ground and anti-air support.

Sugar Cookies

"All player units have 50% more hitpoints."

Unlock requirement: Keep the Scarab's health above 25% on The Foundry.
Notes: If you are attempting to unlock the "Wuv Woo" skull in this mission, this will likely mean your Scarab should have no issue staying above 25% of its health. As mentioned, just take the mission and its objectives slowly and keep your Scarab at the rear. Bring some Nightingales as an escort.

After Party

"Any time a base or minibase is destroyed, the player who owned it gets a tank and infantry unit."

Unlock requirement: Rescue Bravo base on The Halo.
Notes: When the mission starts, you should notice a Power Node just ahead. Capture that Node and then Captain Cutter will inform you of Bravo base; they are under attack and need your help. Move your units to Bravo Base and repel the Banished assault as quickly as possible. This can only be done once you've repelled the Retriever Sentinels' first attack.

Nightmare

"No checkpoints or saves on any difficulty. Campaign only."

Unlock requirement: Keep the Control Room shield over 50% on Last Stand.
Notes: Since you do not have access to base-building during this mission, you will need to rely on the Units that Captain Cutter periodically provides. To start, make sure to build and upgrades turrets around the edges of the central chamber. Focus on building Anti-Infantry and Anti-Vehicle turrets. Next, you'll want to make sure each of the four entryways of the chamber are appropriately defended. Split your focuses intelligently; you'll have access to essentially the entire Halo Wars 2 unit roster. Spread them out evenly and make use of your Leader Powers as often as possible. Always drop ODSTs every time a leader power is ready, since you get an endless population to strengthen defenses further.

Shadow

"Player core infantry units start cloaked."

Unlock requirement: Kill the two Brute Warlords and stop their reinforcements on Last Stand.
Notes: At the beginning of the mission, you will be informed that Brute Warlords are converging on your position. They will both be displayed on your mini-map, but they don't necessarily storm your position; rather, they will remain far away, under the cover of the Fog of War, with their army of reinforcements. Once you have a sizable and formidable squadron of mixed units (Snipers, Spartans, Scorpions, Cyclopses, etc.), storm each Warlord's position to take them and their reinforcements out. Try to complete it in less than ten minutes after the mission starts, or the first batch of reinforcements arrived (8 Marines and 8 Cyclops), since the more time you take, the heavier the Banished attack will get, and you have less of a chance to defeat the Warlords. Use every Leader Power if possible, as you'll need more numbers to defend the Control Room.

Unused skulls

Main article: Halo Wars 2 cut content

The following skulls were cut from the game, with only icons and strings left over in the game files.

Vampire

Effect: All UNSC and Banished units gain the keyword Siphon: This unit has special weaponry that steals health from its enemies equal to the damage dealt..

What's in the Box

The box when the skull is enabled.

Effect: Every 5 minutes, boxes are deployed around the map. The player that interacts with the box is granted a random unit.

Moon Gravity

Effect: Reduces the gravity and explosions, launches victims much further.

Fog

Effect: Disables the heads-up display similar to the Fog skull in the Halo first-person shooters.

Iron

Effect: Similarly to the Iron skull in the Halo FPS games, forces the player to restart a level from the beginning if they fail.

Look Daddy!

Effect: When Grunt units are killed, their methane canisters cause them to fly around (see also: the Halo Wars skull of the same name.

Clear Skies

Effect: Removes fog of war from the map, allowing players to see everything. In the final game this can be applied as a game setting in the skirmish lobby.

Cowbell

Effect: Explosion strength is increased, similar to the Cowbell skull in the Halo FPS games.

Achievements

Main article: Achievements (Halo Wars 2)

There are several achievements in Halo Wars 2 for finding and using skulls, with an additional exclusive achievement in the Awakening the Nightmare DLC. These are as follows.

Icon	Name	Description	Gamerscore
	Lone Wolf	Complete any mission (except The Signal) solo on Legendary with all skulls activated.	40
	Alas, Poor Yorick	Collect a Skull.	10
	Morbid curiosities	Collect half of the Skulls.	20
	Collecting a dream	Collect all the Skulls.	30
	Banished Prowess	Beat any level on legendary in par time with a scoring skull active (Awakening the Nightmare only)	15