On this page of the guide to Halo Infinite, you will find the location of the 11th skull - Black eye. It's a secret to be found during exploration of the open world, specifically in the part of the Zeta Halo visited in Act Reformation. We've posted detailed instructions on how to get to skull number eleven.
The location of the 11th skull - free exploration
This skull is a bit different because you can find it while exploring the open world. It's not found in a location associated with any of the main missions.
The skull is found in the southern part of the Zeta Halo ring which you'll visit for the first time during the Reformation chapter. You need to head east of the FOB Kilo (and to the north of one of the beacons from The Sequence mission).
Your destination is a big waterfall pictured above, you can reach it on foot or in a vehicle.
You must get to the very small rock shelf hidden behind the waterfall - we've marked it on the picture, the grappleshot should prove very helpful here. Grab onto the subsequent fragments of the cliff with the grappleshot.
We recommend having the Quickshot upgrade for the Grappleshot - it costs 2 upgrade points (2 Spartan Cores). It reduces the launchere's cooldown by 40%. It's very helpful in climbing.
If you've managed to climb onto the small shelf by the waterfall you should notice a hole you can squeeze through.
The skull is in a newly discovered cave behind the waterfall.
Black Eye skull - how it works
The skull limits Master Chief's Shield regeneration. Once you activate the skull your shields will only regenerate if you hit an enemy with a melee attack. This significantly raises the game's difficulty, as it often forces you to fight with your shields weakened or disabled until you fight an enemy you can easily attack in melee.