In Quake 4, a Gladiator is a massive, 8-foot tall Strogg heavy unit equipped with a shoulder mounted Railgun as well as an arm-mounted plasma blaster. The Gladiator is also equipped with a large, arm-mounted energy shield that is used as defence from frontal attacks. They are first introduced in Perimeter Defense Station, but they will be more common later in the game and often support other smaller Strogg units.
Gladiators are some of the heaviest Strogg units in the game, second only to Light Tanks and the "minibosses"-like Stream Protectors and Heavy Hover Tanks. Additionally, despite having somewhat less health than a Light Tank or Stream Protector, the Gladiator's damage-deflecting energy shield can make it an even more challenging opponent. Despite their large size making them slower than average, Gladiators can still stalk forward at a decent speed, and will pursue you if you retreat to a different room.
Gladiators primarily attack with their shoulder-mounted railgun, which they fire once every several seconds or so. Gladiators disengage their shields and lean forward just before firing their railgun, which is a good signal to dive for cover. In addition to their railgun, they can also fire a handful of shots from their arm-mounted plasma blaster at medium range. Their plasma shots are very large, but do an average amount of damage (about the same as a Gunner or Light Guard's nails). They can also fire plasma blasts while their shield is still up.
They also have a powerful, arm-mounted circular energy shield, which completely deflects any and all projectiles fired at them (including explosive damage from a direct rocket hit). The shield is large enough to cover most of the Gladiator's body, although its head and shoulders and lower legs are still partially exposed. Gladiators put their shield up as soon as they take damage, and will only drop it just prior to firing off a railgun shot, after which they will put it up again.
Gladiators are always encountered one at a time, although they are usually accompanied by a few Guards or Tactical Strogg units, thus they are considered supporting strogg unit. Although rarely seen compared to other Strogg units, Gladiators are still reasonably common (at least for heavy strogg units), with two or three appearing in many of the game's levels. They are fairly tough and can take more damage than most other Strogg, requiring 40 to 50 Machine Gun or Hyperblaster shots, 4 to 6 point-blank Shotgun blasts, or a handful of direct grenade hits to kill.
- The Gladiator only puts up its shield after being hit, so the first shot will almost always hit and cause damage. With the shield disengaged, it is a good opportunity to hit the Gladiator with a rocket or a spray from the Nailgun. The Lightning Gun may be used to overpower the shield generators, and disable the shield for a brief amount of time, giving a chance to attack. In addition, the shoulder-mounted Railgun is always vulnerable, so it may be shot to cause damage.
- The Grenade Launcher is a great weapon against Gladiators, especially for players who lack firepower. If a grenade lands anywhere near the side or the back of a Gladiator unit, the explosion will cause moderate damage to that unit, even with the shield activated. A direct hit will cause it to be stunned for about a second. The grenade launcher is also semi-auto, means you can deliver 4 to 6 grenades before it fire at you, which is an efficient tactic. If you run into Gladiator in close quarters and corridors, use grenade launcher to keep dumping explosives while retreating, this will cause the Gladiator to keep taking damage, while it struggles to catch you.
- While the Gladiator's shield covers most of its head, there is a chance to shoot the top of the head. This has been an effective method in eliminating Gladiators at long range. It is also possible to damage the shoulder-mounted railgun, making it explode. This will make the Gladiator charge at the target with the shield engaged, which might make it harder to destroy.
- Avoiding the Gladiator's attacks is surprisingly simple. Before the Railgun is fired, a Gladiator disengages the shield and bends forward to allow an accurate railgun shot, the railgun itself will light up before it was fired. This gives a chance to cause some damage, because it will take about two seconds for the shot trajectory to be calculated. The railgun beam is extremely fast, but it may be dodged by moving around, confusing the calculation and causing the beam to miss. Its plasma blaster attack is somewhat fast, but can be avoided at moderate range, its better if you are in cover. If you are not prepared, just take cover while its Railgun is lighting up.
- A Gladiator Strogg unit is always surrounded by weaker units, such as Tactical Strogg and Guard. A battle with a Gladiator is usually a battle of attrition, meaning the weaker units should be disabled first so that all attention is directed on the Gladiator. Stay away from the Gladiator and let the cannon fodder come closer, if you are "stucked in a phonebooth" with them, use Grenade Launcher, Shotgun or even Dark Matter Gun to save yourself quickly, or there is a good chance they will finish you.
- In early game, Gladiators usually fight with other Strogg units, cannon fodders like Guards will often get in your way while you are dealing the biggest threat, because you lack firepower, fighting them head on is not recommended. Find a safe place to dispatch these smaller units first will make your combat with Gladiator safer. If they are close together however, use Grenade Launcher to hurt everyone.
- The Gladiator unit has a capability of a melee attack against targets at close range, making them deadly in close quarters combat. They should be engaged at a moderate or long distance, you can easily retreat due to their slow moving speed.
- The Gladiator's Rail Gun is vulnerable and capable to destroy with any weapons. Destroying it will disable the Gladiator's rail gun use and he will rely more on his plasma gun and his shield, which will make him vulnerable to long-ranged attacks. So if you can, aim for its rail gun first and fire, Gladiators usually won't attack for about 2 seconds once you encounters it, you can use this to your advantage, either attack or retreat to a better spot to engage.
- Compare to other foes, Gladiator is fairly slow and large in size, if you have problem using the Railgun on the other smaller or faster enemies, use it against the Gladiator. Despite using the similar Railgun, Gladiators never drop ammo.
- If you shoot directly at the Gladiator's gun, you can actually destroy it. This will force him to use melee attacks only.