The Skulls made popular in Halo 3 are again scattered in many obscure locations throughout the various levels of Halo Wars campaign mode. Some Skulls increase the game's difficulty and score, others reduce difficulty and score, while others have been added just for fun.

Throughout each level's Campaign mode, skulls will appear on the map. Complete the assigned objective to kill a specific number of a certain unit type to earn it. For example, kill 100 Grunts in Mission 1's Alpha Base. The objective pops up with a counter each time a unit of the designated type is killed to help track progress. Once earned, the Skull location will flash on the mini-maps for a few moments so be sure to keep an eye on the map as you complete the objective. When the objective as been met, the Skull is accessible via the menu in either Campaign or Skirmish modes. Activate the Skull to trigger its special effect.

Each mission begins with all Skulls deactivated. They may be activated at any point during the mission. Once activated, however, they may not be deactivated until the mission has been completed.

At the end of each level, you receive a cumulative score based on the primary and optional objectives that have been completed, combat bonus calculated from the ratio of enemies killed to allies lost, time bonus and Skulls bonus. Your score determines if you receive a gold, silver, bronze or tin award.

• Skulls within each level of the Campaign mode display once that level's kill requirement is met. These are listed below for each Skull as well as the Skull's location and special effect. Activate Skulls from the pause menu.

• YouTube Video: Halo Wars Skull Locations (Time: 2:25)

• This page contains spoilers for the skull locations throughout Halo Wars.

• Skull name: Look Daddy!

• Kill requirement: Kill 100 grunts

• Mission 1: Alpha Base

• Location: Once all one hundred Grunts have been killed, get a Warthog and return to the front gate of Alpha Base to the embankment near the downed ghost where last set of marines are found.

• Special effect: When grunts die, their methane tank explodes

• Skull name: Grunt Birthday Party

• Kill requirement: Kill 20 Jackals

• Mission 2: Relic Approach

• Location: After killing the twenty Jackals, return to Alpha Base with a Warthog. The Skull is at the southwest of your starting base location in front of damaged gate.

• Special effect: Grunts explode into confetti

• Skull name: Cowbell

• Kill requirement: Kill 45 Hunters

• Mission 3: Relic Interior

• Location: Take one Grizzly (after killing the 45 Hunters) to the front of the main console where Forge and Anders are initially pinned down. The Skull is on the central pad.

• Special effect: Destruction physics magnified x2

• Skull name: Wuv Woo

• Kill requirement: Kill 50 Elites

• Mission 4: Arcadia City

• Location: After killing the fifty Elites, return to Base Two and look for the stairs leading to a bronze statue. The Skull is next to the statue.

• Special Effect: Scarabs shoot rainbows made of pure love

• Skull name: Fog

• Kill requirement: Kill 5 Wraiths

• Mission 5: Arcadia Outskirts

• Location: Kill the five Wraiths and bring three Warthogs to the tracks to the left of the Main Base. Continue straight until you reach the split in the tracks.

• Special effect: No minimap. Final score will increase by 10%

• Skull name: Sickness

• Kill requirement: Kill 50 Banshees

• Mission 6: Dome of Light

• Location: Kill the fifty Banshees and take a squad of Marines to the Hanger immediately behind your Base.

• Special effect: All player units have 50% fewer hitpoints. Final score will increase by 10%

• Skull name: Rebel Sympathizer

• Kill requirement: Kill 10 Locusts

• Mission 7: Scarab

• Location: After killing all ten Locusts, take a Warthog to the top left of the map to the two Locusts and Power Nod

• Special effect: Non-player units get 25% more hitpoints. Final score will increase by 20%

• Skull name: Rebel Supporter

• Kill requirement: Kill 750 Infection Forms

• Mission 8: Anders' Signal

• Location: Head to the north side of the map after you have killed the 750 Infection Forms where you bagged the elephant. Head east until you come to a cliff. Take a group of Marines down the ridge to find the Skull.

• Special effect: Non player units do 50% more damge final score will increase by 20%

• Skull name: Rebel Leader

• Kill requirement: Kill 20 Flood Stalks

• Mission 9: The Flood

• Location: Kill the twenty Flood Stalks and head to the downed Pelican to the northeast of Main Base with a Warthog.

• Special effect: Non-player units star with extra veterancy. Final score will increase by 20%

• Skull name: Catch

• Kill requirement: Kill 350 Swarms

• Mission 10: Shield World

• Location: Once all 350 Swarms have been killed, take two Hornets and fly east of the Base past the first Tower to the Plateau covered with Flood Eggs. The Skull is in the center of the Plateau.

• Special effect: All player units recharge unit abilities in half the time. Final score will be decreased by 20%

• Skull name: Sugar Cookies

• Kill requirement: Kill 100 Sentinels

• Mission 11: Cleansing

• Location: Kill the hundred Sentinels and take a Hornet to the front end of the Spirit Of Fire. The Skull is located on the nose of the Ship.

• Special effect: All player units have 50% more hitpoints. Final score will decrease by 50%

• Skull name: Boomstick

• Kill requirement: Kill 12 Spirit Transports

• Mission 12: Repairs

• Location: Take a Hawk to the lower 2 Airlocks after you have killed the twelve Spirit Transports. The Skull is located on the little ramp in the air.

• Special effect: 5% chance any non-player unit blows up upon death with explosive area of effect damage. Final score will decrease by 10%

• Skull name: Pain Train

• Kill requirement: Kill 10 Bomber Forms

• Mission 13: Beachhead

• Location: After killing the ten Bomber Forms, return to the First Teleporter at the beginning of the map. Follow the path to a Flood nest. The Skull is next to it.

• Special effect: All player units train 50% faster. Final score will decrease by 25%

• Skull name: Bountiful Harvest

• Kill requirement: Kill 20 Vampires

• Mission 14: Reactor

• Location: Head to the Second Covenant Base after killing the twenty Vampires. The Skull is in the far corner at the bottom of the ramp.

• Special effect: Supplies come in 25% faster. Final score will decrease by 30%

• Skull name: Emperor

• Kill requirement: Kill 3 Scarabs

• Mission 15: Escape

• Location: Arm yourself well and make your way to the center of the Flood at the north of the map after killing the three Scarabs. Scarabs are only spawned every nine to eleven minutes, so there is no quick way to kill them.

• Special effect all player powers recharge in half the time. Final score will decrease by 50%