On this page of the guide to Halo Infinite, you will find the location of the 4th skull - Grunt Birthday Party. This is one of the skulls you can obtain while playing through the campaign, namely one of the main missions - Repository. We've posted detailed instructions on how to get to skull number four.
Location of the 4th skull - Repository main mission
You can only obtain this skull during the Repository mission. It's not available during free exploration of the Zeta Halo ring.
The starting location will be a large hall with a relay which activation begins a cut-scene starring the Weapon and Escharum. Don't leave this room.. In order to obtain the secret, you must perform additional actions in this room before you proceed further.
Turn 180 degrees to stand with your back to the currently ignored destination marker. You must follow the route shown in screenshot 1:
- cross the bridge and turn left,
- reach the edge. aim for the upper support and use Grappleshot to connect to it.
- jump to the adjacent platform from screenshot 2.
In the newly discovered area, go to the door on the upper level. It will lead you to a room with a power seed.
Now you must carry the seed back, which means returning to the main hall and using Grappleshot to return to the central area.
- If flying guards are too much a hassle, lay the seed on the ground and deal with them. You also can simply ignore them and run away with the seed.
- Even if you lose the seed, you can return to its origin location and take a new one.. .
All the while carrying the seed, you need to reach the balconies on the opposite side of the room - step by step instruction:
- run towards the exit from the large hall, ignore it and turn left,
- use Grappleshot
- jump to new shelves.
Same as before, use the upper door. Linear corridors will lead you to an inactive generator in which you must put the carried power seed.
Now you can continue back with the mission. For the last time, use the Grappleshot and use the path shown by the mission marker leading to further rooms of Repository.
Further along the way, make a habit of selecting left corridors in every newly visited rooms. Thanks to this, you won't miss the second part of the skull puzzle.
If you've activated the generator from Part 1 correctly, the left door seen on the screenshot will be opened. Once opponents are defeated, follow this new corridor.
In the new room use the Grappleshot to ascend to a higher level.
Beware of stealthed enemies wielding blades - use the sensor if they are too much. You can also use grenades to make them come out of hiding. If necessary, jump down to have more room for movements.
The skull will be in the place where the enemies where.
Grunt Birthday Party skull - how it works
The skull unlocks a visual emote (and confetti) after headshoting grunts. It is a type of an easter egg.