- "Back in your hole!"
- —Marcus Fenix
Emergence Holes, otherwise known as E-Holes, were ground-level openings into subterranean tunnels dug by the Locust Horde to allow military units to breach and invade the planet's surface. The Locust Horde appear to be capable of digging into most substrata, including both natural and artificial stone formations. While Drones were capable of digging smaller E-Holes; indigenous creatures from the Hollow enslaved by the Locust Horde, such as the Corpsers and Seeders, were capable of producing massive E-Holes to deliver hundreds to thousands of troops.
The only area of Sera generally immune to these tunnels is the stone-impregnated Jacinto Plateau because of its solid granite bedrock. Natural fissures and utility tunnels provided occasional access to emerge within cities located on the plateau, but Jacinto City remained the only city unable to the Locust to emerge in. However, in 14 A.E., the granite base was weakened by the Locust Horde utilizing the Riftworm to sink cities on the plateau, allowing Jacinto City to be vulnerable as well. Other areas the Locust Horde were unable to dig through were islands in the Serano Ocean, due to the Abyssal Trench.
Earthquakes and tremors usually precede the opening of an E-Hole. The tremors of an E-Hole could be so great it that could incapacitate those near it. The tunnels leading into surface are usually so tall that falling into one is often times fatal. Emergence Holes would spawn a set amount of Locust before collapsing naturally. E-Holes could be collapsed prematurely by explosives, usually by grenades or the Hammer of Dawn.
Gears of War 5 Hivebusters campaign DLC confirmed that Pahanu was also impossible for the Locust to tunnel through due to the positioning of the islands, which is why Sanctum was built on the island.