Sledge is an intergalactic bounty hunter who prides himself on capturing monsters (which he sends to fight the Rangers) and collecting the bounty on their head, as well as collecting asteroids. He is rather ill-tempered to his subordinates, though he does show a softer side to his fiance Poisandra. He plans to capture the Energems and gain ultimate power for himself. During pre-historic Earth, Keeper set a trap, setting his ship away from Earth and his asteroids caused the extinction of the dinosaurs. He tried all he could to get the Energems from the Rangers, he ultimately got the Purple and Red energems but was thwarted by the Red Ranger and is presumed destroyed.
Fury is the ill-tempered and irritable general to Sledge, who wields a Seven-Branched Sword that can harness lightning. After arriving on Earth, Fury is sent to capture the Energems from Keeper. But Fury falls for a trap set by Keeper that crippled Sledge's ship. Though assumed to have been caught in the asteroid debris, Fury survived and became a reoccurring nemesis to Keeper for millennia. Tyler believes Fury to be connected to the disappearance of his father, even though the two met, his father was safe. SIr Ivan was trapped inside of Fury for a couple of hundred of years until the Rangers helped him escape. Fury now serves Heckyl/Snide.
Wrench is another of Sledge's generals who has a whiny personality if he is badly hurt. Though he serves as the ship's technician, Wrench can use a battle axe in a fight. Wrench was also the one who created Curio for Poisandra. Wrench created various devices such as a device to use Ivan's energy, a weapon using the Energems, a monster duplicator and other devices.
Poisandra is Sledge's heart-themed fiance and her own agenda is to get married to Sledge. However, he constantly puts their marriage plans on hold due to his immense greed. Poisandra has musical-themed attacks. When Sledge got the Red Energem, Poisandra was ready to leave Sledge but once he was believed to be dead, she mourned him. Under Heckyl/Snide's reign, she barely ever goes down to Earth but does make the odd comment here and there.
Curio is a doll-like companion of Poisandra that Wrench created out of spare monster parts as an early wedding present while doubling as a means to keep Poisandra at ease while Sledge focuses on retrieving the Energems.
The Vivix are the foot soldiers of Sledge's group. The Vivix can combine into large monstrous creatures called Vivizords where this form enables them to fight the Dino Zords. A random Vivix would be used to operate the Magnabeam.
The Vivix can combine into large monstrous creatures called Vivizords where this form enables them to fight the Dino Zords.
Heckyl was one of Sledge's captives in his ship behind a heavy locked door. Sledge let him out in order to trick the Rangers as he was the only one who looked human. Heckyl is charming, underhanded and vicious, the other monsters fear him. He saved Kendall from a car once and she hired him for her cafe, he managed to find their base. But because he drank a mind-wiping potion, he forgot the location of the base. He is much more calculated and higher-thinker than Snide. Shelby discovered he was actually against them and then he became Snide, sealing the deal.
Snide is Heckyl's monstrous side, they exist in the same body. When Snide is in charge, he can see Heckyl on his sword. When Heckyl is in charge, he can communicate with Snide on his pocket watch. Snide is ill-tempered and all about brute-force. The Rangers met him before Heckyl.
Singe is an alien who arrives in a burning ship on Earth, met Snide and he partners up with him to get the Energems. He does not get along with Fury, they often argue and Heckyl traps both of them in the same prison. Singe is upstoppable against the Rangers, grows big but because he is winning, Fury shrinks him down. Singe also uses Zotak rings on the Rangers' energems and even on Fury to de-power him.