The Fiendian Reptiloid Demon is a demon-like creature that throws lava balls. It is actually a different species compared to the similarly-named Aludran Reptiloid. The Fiendian Reptiloid Demon was originally a simple lizard from Fiendia Prime, but was mutated by Mental over several generations to create the Demon. It is one of the few immobile enemies in the game.
In most occurrences, Demons are placed far away from the player to harass the player while they are fighting off other enemies. They can usually be found in elevated places such as towers, roofs and pillars. Usually only one to few appear at a time but there are instances where several of them appear. They are much more common and numerous in higher difficulty levels.
The Demon has two attacks. Its primary attack is throwing a large lava ball at the player. This ball is extremely fast. It cannot be destroyed in the classic version of the game except by a cannonball or a few laser beams. However, in the HD version, it can be destroyed using any weapon. If the ball does not hit the player at first, it will fly past them and attempt to circle back and hit them again, exploding should it miss a second time, or explode instantly if it hits a flat surface.
Its secondary attack is hitting the player if he gets too close. This attack is difficult to avoid.
- The player should not try to get close to a Demon, even if the Demon is on an elevated position. When close to the Demon, the lava ball is too fast for the player to dodge.
- Generally, demons are more dangerous in very open spaces as a fireball which doesn't hit a wall comes back at player and can do so a few times.
- While the ball thrown by the Demon is easy to avoid at medium or long range, the demon can be deadly if it is in a tight or indoor area. If it appears in one of those areas, it should be one of the first enemies killed.
- The RAPTOR Sniper Rifle is very effective against this enemy, because it it is frequently placed in faraway areas.
- Multiple faraway Demons can be dispatched with the XM214-A Minigun. Its high rate of fire and perfect accuracy make it a great weapon for quickly taking out multiple Demons.
- If the player wants to conserve bullets or RAPTOR ammo, the XPML21 Rocket Launcher is effective against Demons. Because it never moves, it is easy to land multiple rockets on it in a very short amount of time. However, If used at medium or long range, at least one rocket will be destroyed by the lava ball thrown by the Demon when not sidestepping.
- While Demons can move, most of them aren't designed to move in the original game, but in the HD remakes they will move if the situation is needed (for example, if the Demon is on the same level as Sam and if Sam tries to hide behind something that the lava ball won't hit, the Demon will adjust its position to attack you.)
- In most cases, Demons will be acting as snipers in big battles, because while front forces attack you, Demons are usually positioned on towers very far away on the field, and since their fireballs travel extremely fast, they can accurately dispatch the player if he is not paying attention.