Shield Bearer is a name given to two distinct types of enemy in the EDF series: the first type appeared in Global Defence Force and also appears in Earth Defense Force 2: Invaders From Planet Space, while the second appears in Earth Defense Force 2025 and Earth Defense Force 4.1: The Shadow of New Despair.
Global Defence Force
The Shield Bearer or Mirror Saucer is a chrome-silver variant of UFO with a red underside and spiked projections, first seen in mission 18: Evil Mirrors. It has no offensive capabilities and acts as a support unit.
Rather than attacking, Shield Bearers will turn to face their underside at the player character and open out slightly. While in this state, any gunfire that strikes the silver parts of their body will be reflected at the player character (this includes enemy weapon fire that hits the Shield Bearer). The red "bull's eye" of the vehicle is the only point where shots are not reflected, and is its weak point.
They are strong against weapons that would normally be useful against aerial foes like the Infantry's assault rifles and the Pale Wing's electroshock weapons, but weak against precision arms such as sniper rifles and Lances. They can reflect rockets and missiles that strike them directly, but can be harmed by splash damage.
One point of note is that reflected attacks are still subject to their normal maximum range: as a result, shooting them from close to the limit of a weapon's range will mean any reflected shots cannot actually make it back to the player character before disappearing.
While the vehicle that appears in 2025 and 4.1 has the same name, the similarity basically ends there. The Shield Bearer in this version is a fragile-looking quadruped walker about as tough as a Hector. They carry a Shield Screen generator on their back, which creates a translucent dome-shaped barrier that blocks almost all weapons fire including the Air Raider's strikes, but can be entered by infantry and vehicles.
Shots that strike the shield create a bright flash at the point of impact. The screen also reflects ambient light, and can appear almost opaque from certain angles.
While the description of slow-moving objects not being stopped might lead one to think that slow weapons like the Tempest missile, Air Tortoise or Leviathan will be allowed though, this is not the case. The Air Raider's Roller Bomb will also bounce off a Shield Screen, though oddly the Patroller will pass straight through: this appears to be because the game engine handles the Patroller as an NPC rather than a projectile.
A few types of weapon can fire through Shield Screens. The Fencer's Force Axes and the stage 3 charge of the Dyna Force Blade also do this, as do the Wing Diver's Thunder Bows with the secondary reflections of their shots (the initial shot will bounce off, but a shot that has already bounced will pass through). This appears to be intentional, since the engine will tag any projectile that passes through a Shield Screen, preventing it from dealing damage to the Shield Bearer itself. Nothing else inside the screen benefits from this protection, however.
There is only one attack type which can pass through a Shield Screen and harm the Shield Bearer: this has been dubbed a "Type A" flame online. There are only two weapon types in the game that create flames of this type: the Ranger's Flamethrower weapons and the Incinerator mounted on the Depth Crawler. All other flame weapons produce "Type B" flames which lack this capability.
The Shield Screen's size is set on a per-enemy basis rather than being fixed. Shield Screens can overlap; if they do, they all "count" as existing. This is particularly relevant in missions like Labyrinth of Light which feature deliberately overlapped Shield Screens of various sizes.
Shield Bearers have two possible states; the first is their "deployed" state, with the legs locked and the shield generator raised high. In this state their shield increases in size. Some Shield Bearers are locked in this state, such as the two in Shining Stronghold.
Other Shield Bearers can move; to do so, they will lower their generator and unlock their legs, trundling slowly to a new position. Mobile Shield Bearers can only be in their deployed state for a limited amount of time before having to move, even if nothing has happened, but will move immediately if they are attacked. The change in the shield's size means that it may shift from being behind the player character to in front of them; thus, care must be taken when using any weapon that can damage the player character.
In 2025, they are very slow and tend to just trundle around aimlessly. NPCs tend to ignore them unless they are led inside the Shield Screen by the player character, and so leaving one alive provides excellent opportunity to gather Items.
It is also important to keep in mind that they do not drop items in 2025 when killed and are the only ground-based non-boss enemy that are not continuously spawned. While they are said to be deployed from Transport Ships and the Mothership in mission briefings, there is no point when this actually occurs during gameplay.
In 4.1 mobile Shield Bearers are totally changed, with new AI and radically different behaviour. They are now extremely fast and will actively seek out enemies to protect, following them as they move. While protecting a specific enemy, they will move close to it, switch to their deployed state, and then undeploy and catch up as the enemy steps outside of their Shield Screen. If there is nothing for them to protect, they will run away in the opposite direction to the last one they were attacked from.
NPCs are more aggressive towards them and will move inside the Shield Screen to attack them, and usually if one is left alone they will destroy it themselves after a while.
There is also now an "Elite" Shield Bearer which projects a dome some three times larger than a normal one. They are first seen in Brute Force, where one of them is added when the second group of Hectors arrives. These vast Shield Screens can have entire ordinary Shield Screens under them, making them very dangerous.
In this version, Shield Bearers do drop items when they are destroyed, usually 3-4.