They are the Thing Things that want to see 154 dead in front of them. They are always aggresive, attacking on sight. They are mercenaries hired by none other than Systems Corp to kill 154. They come in numerous classes-
Soldiers are the weakest form of enemy in Thing Thing 4 and Arena 2. They are mainly cannon fodder enemies, being weak. They are also the most common, appearing in large mobs. They aren't very strong, but in groups, they are pretty annoying.
They come in several kinds of costumes-
Helmet and Vest- the most common. (In TT4, the helmet got more detailed)
Gas mask and vest- Somewhat weaker then others.
Odd visual object and vest- Same as Helmet soldier
Squad captains are the second class of enemies. They are much stronger then the Soldiers. They wear a helmet similar to the soldiers, but it has more grooves and has a red visor. They also wear a vest with a spike on the back. In TT4, the helmet got more detailed.
The strongest enemy in Thing Thing Arena 2 and the second strongest in Thing Thing 4. These dangerous enemies wear a large skull like helmet, and wear a vest with numerous sleeves. They are the least common, but are very dangerous due to their large health. In Arena 2, the sleeve on the bottom was black, but in TT4, it is white.
These enemies are the strongest enemies in the TT4. They wear the same clothes as Skull Majors, but it is black with red lights coming out of the helmet. They have huge health (almost 3 times as much as soldiers) and are incredibly annoying to take down. They are also candidates for the Desert Eagle, so watch out! However, in TTA3, since Black is a costume color option for enemies, Black Skull Majors are no different from the other colors.