Gatekeepers are powerful psionic units that can float, deal significant psionic damage, and reanimate corpses as zombies. They have high HP and armor. Their reanimation ability can quickly overwhelm your squad if not managed. Prioritize eliminating them quickly to prevent a zombie horde.
Strategy:
- Focus Fire: Concentrate all damage to eliminate them before they reanimate.
- Psi Operatives: Null Lance and Mind Control are highly effective.
- Flashbangs: Disorient them to prevent psionic abilities.
- Shred Armor: Grenadiers can help reduce their defenses.
- High Damage: Rangers with Rapid Fire or Sharpshooters with Serial are good.