Hey, I know there have been a couple of other skull thread, but I thought I would start a new one that is specific to confirmed skull locations and that has some information I haven't seen posted yet.
First off, this community is awesome. I haven't been here for years since I helped get it up and running way back in 2006. I want to commend everyone that has stayed around since than. I probably won't stay long again, but I just wanted to drop by with some information I haven't seen posted yet.
Now, how to find the skulls. Each level in Halo Wars has an optional objective where you are asked to kill a certain number amount of a certain unit type, such as killing 100 Grunts in the first mission, Alpha Base. Once this objective has been completed, the skull location will flash on the mini-maps for a couple seconds, so it's important to watch the map as you complete the objective. To simplify this, the objective will have a counter that pops up every time you kill a unit of the designated unit type. Example, the HUD will show "56/100 Grunts Killed" or something similar. Here is the information I have managed to find thus far. One last thing to note, is that the skull will not appear in it's location until the objective has been met.
Mission 1: Alpha BaseSkullname: Look Daddy!
Location: On embankment near the downed ghost where last set of marines are found (Indie)
Kill 100 grunts.
special effect when grunts die their methane tank always shoots off
Mission 2: Relic ApproachSkullname: Grunt Birthday Party
Location: Southwest of your starting base location in front of damaged gate (Indie)
Kill 20 Jackals
special effect grunts explode into confetti
Mission 3: Relic InteriorSkullname: Cowbell
Location: In front of the main console where Forge and Anders are initially pinned down (Indie)
Kill 45 Hunters
special effect destruction physics magnified
Mission 4: Arcadia CitySkullname: Wuv Woo
Location: Very eastern part of the map near statue of man holding book (Indie)
Kill 50 Elites
special effect scarabs shoot rainbow made of pure love
Mission 5: Arcadia OutskirtsSkullname: Fog
Location: north west of map on top the highway near two buildings (raptor00)
Kill 5 Wraiths
special effect no minimap final score will increase
Mission 6: Dome of LightSkullname: Sickness
Location: In the hanger behind your base (raptor00)
Kill 50 Banshees
special effect all player units have 50% fewer hitpoints final score will increase
Mission 7: ScarabSkullname: Rebel Sympathizer
Location: Next to the power node to the west of the scarab (raptor00)
Kill 10 Locusts
special effect non-player units get 25% more hitpoints final score will increase
Mission 8: Anders' SignalSkullname: Rebel Supporter
Location: On cliff edge beside a crevas in the northern part of the map (raptor00)
Kill 750 Infection Forms
special effect non player units do 50% more damge final score will increase
Mission 9: The FloodSkullname: Rebel Leader
Location: By the downed pelican to the west of your starting base (raptor00)
Kill 20 Flood Stalks
special effect non-player units star with extra veterancy final score will increase
Mission 10: Shield WorldSkullname: Catch
Location: On the island in the south east section of the map (you need air units to reach it) (raptor00)
Kill 350 Swarms
special effect all player units recharge unit abilities in half the time final score will be decreased
Mission 11: CleansingSkullname: Sugar Cookies
Location: North east section of the ship in between both platforms (you need air units to reach it) (raptor00)
Kill 100 Sentinels
special effect all player units have 50% more hitpoints finla sore will decrease
Mission 12: RepairsSkullname: Boomstick
Location: North east section of the ship above the central stucture (raptor00)
Kill 12 Spirit Transports
special effect 5%chance any non-player unit blows up upon death with explosive area of effect damage final score will decrease
Mission 13: BeachheadSkullname: Pain Train
Location: In the first area you start in near the flood buildings (west of map)
(raptor00)Kill 10 Bomber Forms
special effect all player units train 50% faster final score will decrease
Mission 14: ReactorSkullname: Bountiful Harvest
Location: North-most part of the map near the second covenant base (raptor00)
Kill 20 Vampires
special effect supplies come in 25% faster final score will decrease
Mission 15: EscapeSkullname: Emperor
Location: North East of the map near a hot water spring and a flood base (raptor00)
Kill 3 Scarabs
special effect all player powers recharge in half the time final score will decrease
Credits: Indie and raptor00 from Halowars.com forums
Hopefully when the game comes out, map images will also start to pop up so that we can pinpoint them exactly with an image.