Infected

Infected are hostile undead creatures that were likely once Ratizens who succumbed to an unnamed infection long before the Leader arrived. They are tied to the Den of Plagues, where their corpse lies dormant until the den is damaged or a raid begins. When awakened, the den emits a green glow, making it one of the main signs that an Infected attack is imminent.

During an invasion, Infected will assault the base directly. If they cannot find a route to their target or are too far away, they create a tunnel toward the nearest building and attack through it. These tunnels can be collapsed by destroying them, which can help stop an attack before it reaches important structures. Their behavior makes them especially dangerous in enclosed or badly defended bases, since they can bypass ordinary ground routes and force the player to respond quickly.

Destroying a Den of Plagues rewards 60 Sharp Tooth, but the reward is dropped in a loot chest that must be claimed before it expires. After reaching Prosperity 4, Infected stop assaulting the base as a normal invasion threat. Existing dens can still spawn Infected during raids, however, so the den remains dangerous even after the standard attack progression is over.

In practice, the safest way to deal with Infected is to destroy their den before it can spawn attackers or to collapse the tunnels they create before they reach key buildings. Since the den signals its activity with a green glow, it is worth checking damaged dens immediately rather than leaving them unattended.