Tail Soldiers are the base evolution of the beings who evolved from the base Jashinka one-cell organism that came to Earth from space from prehistoric times, reaching this humanoid form and gaining some form of sentience but not to the level of power and capability of higher-evolved beings of the race who have greater power and ability from possessing more tails from birth. While typically used as grunts, they have slight intelligence, including some having the capability to speak in Tail Soldier form. They can also use their abilities to change into human forms in order to disguise themselves and blend in with normal humans; many times they can perfectly appear as human until they are hit or weakened, making their one-tail emerge from behind.
Even though they are typically seen as evil, some can blend in to human society to the point of being capable of living within it even without complaint or hatred of their enemy. Two Tail Soldiers were made to become spies on the surface ten years prior to the series by the Jashinka in order to investigate human society; however the duo eventually chose to stay human and live among them, even having a son without telling the Jashinka of their actions and of their feelings. When the Jashinka force them to use their child to kill a member of Dynaman, they are force to oblige until they rebel to save his life. After the Dynaman rescue them, they choose to move away in order to keep their peaceful lives, still without revealing the truth to their child for his sake.
Several Tail Soldiers were part of an army of past enemy grunts that were fought by the Gokaigers in Los Dark's ghost dimension which housed the 1500 spirits of the villains defeated by the Super Sentai. After losing some of their number in an initial skirmish, the remaining members from each grunt group merged to form the Combined Combatant. Though the stronger opponent, the Combined Combatant proved to be unstable due to internal conflicting among the grunts composing him over who got to finish the pirates off. Taking advantage, the Gokaigers used the Battle Fever J Ranger Keys to destroy the Combined Combatant with the Penta Force cannon.
- The Tail Soldiers are known as the "Reptiles That Go 'Whee!'" in the parody.
- First Sentai minions to be given the "soldier" title.