They are alien monsters dispatched by Damaras or Emperor Mavro.
Headridge was the first alien monster that is sent by the Armada, leading X Borgs into attacking some humans until the Super Megaforce Rangers arrived. He was destroyed by the Super Megaforce Rangers' Final Strike.
Tentacus is a tentacled alien monster who is sent down by the Armada following Headridge's destruction. Tentacus was destroyed by the Legendary Megazord.
A robotic alien who is sent down by the Armada to oversee the missile-launching upon the major cities of the world. Troy uncovers the plan and Cybax is destroyed with the Legendary SPD Megazord. He resembles a Troobian.
"Earth Fights Back"
A master swordsman alien whose sword skills are so good that he can even slice through buildings, perform the Blade of Infinity attack, and perform the Infinity Octo-Blade attack. He is defeated by the Blue Ranger and destroyed by the Legendary Mystic Force Megazord when giant.
"Blue Saber Saga"
An alien high-ranking Armada general with a cybernetic left arm that possesses super-speed. He is sent by Damaras and Levira to look for the Red Lion Wild Zord on Animaria.
"A Lion's Alliance"
A member of the Elite Guard who is sent by Emperor Mavro to assist Prince Vekar in attacking Earth.
A magnetic monster with retractable arms on his shoulders whose hand-to-hand combat is known to beat any of his opponents. While Jake and Emma were trained with Casey Rhodes, with their newly developed animal spirits, thus defeating him in the process. As the rangers used the combined animal spirits of Jungle Fury, and the Legendary Megazord's power, to destroy him.
"Spirit of the Tiger"
A monster who leads an army of X Borgs into attacking the center of the city in order to detonate a bomb there. Besides performing energy attacks from his hands, he can use a force field collar on him that can block attacks. Destroyed by the Silver Rangers' Silver Spear.
"Silver Lining, Part 1"
A rhinoceros-like monster who is summoned by Damaras to destroy Orion. He is destroyed by the Q-Rex Megazord's Triple Drill attack.
"Silver Lining, Part 2"
A green skeleton monster with a skeleton fish for a left arm. He wields a fishing rod-type weapon to drain human energy from people and can shoot lasers from his skeleton fish arm. He is destroyed by the Q-Rex Megazord's Triple Drill attack.
"Power of Six"
A star-shaped monster. He was sent by Damaras to put a stone on a rock that Vrak was working on, but never finished completing. Sirjinkor was destroyed by the Legendary Samurai Megazord's Fire Smasher attack.
"The Perfect Storm"
A monster who had a childhood crush on Levira who can perform fire-based attacks. He created a love potion to make Levira fall in love with him only for her to fall in love with Jake. Invidious was defeated by the Legendary Samurai Megazord's Fire Smasher attack yet survived.
"Love is in the Air"
A monster who wields a staff that can steal human happiness and wears a belt that enable him to size shift and turn invisible. He can also perform wind attacks, shoot eye beams, sprout tentacles. Desolar was sent by Levira to steal all the humans' happiness in order to cure Prince Vekar's cold. Destroyed by the Legendary Q-Rex Megazord's Transwarp Attack.
"United as One"
A monster that can swap the bodies of anyone and emit tentacles. He was sent down to swap the bodies of specific people in order to infiltrate Earth's government only to end up swapping Jake and Noah's body in the process. He was destroyed by the Legendary Ninja Megazord's Ninjazord Attack.
"The Grass is Always Greener... or Bluer"
A turtle-like monster. He wields a hyper dense shell shield which protects him from harm and can shoot energy lightning. He was sent down to distract the Rangers while Tranceferer continues his job. He was destroyed by the Super Mega Cannon.
"The Grass is Always Greener... or Bluer"
A robot from the alternate future of Power Rangers RPM first defeated in "Clash of the Red Rangers: The Movie." Being rebuilt sometime after that battle (except with his screwdriver and wrench hands mirrored from his previous appearance), Professor Cog unleashed the Turbo Falcon Zord on Corinth as a diversion so that he and an army of Grinders could escape to the Megaforce Rangers' reality to invade Earth. He was destroyed by Legendary RPM Megazord's Grand Prix attack.
"In the Driver's Seat"
A member of the Elite Guard with long claws that serves Emperor Mavro. When the Armada reinforcements arrived, Redker decided to battle the Super Mega Rangers himself, only to be defeated while distracted. Redker used a large mallet as a weapon during battle as well as protrude dual razors from his arms in order to slash and cut his opponents apart.
"Emperor Mavro", "The Wrath" and "Legendary Battle"
A member of the Elite Guard that serves Emperor Mavro. He disappears and is never mentioned again. He is assumed to be on one of the ships the Rangers destroyed. "Emperor Mavro"