Upon learning of the Overdrive Rangers, Mack joins them with encouragement from his confidante and butler, Spencer, and against Andrew's wishes in an effort to prove himself.
Following several missions, Mack sacrifices himself to defeat Flurious, but the Sentinel Knight uses the Corona Aurora to revive him and transform him into a human.
In combat, Mack possesses super-strength, which he initially believes is the result of genetic enhancement before learning he was upgraded, and wields the Drive Lance.
William "Will" Aston is a suave and quick-witted yet womanizing and cocky spy-for-hire and the Black Overdrive Ranger who appreciates the finer things in life, enjoys any chance to prove his skills against sophisticated security devices, and tries to maintain a superior-minded appearance.
Dax Lo is a talkative yet enthusiastic stuntman and the Blue Overdrive Ranger who dreams of becoming an actor and appreciates jokes, but can get serious when the situation calls for it.
[19][20] Despite learning Flurious had empowered the Fearcats, Tyzonn initially refuses to work with the Rangers out of fear of losing them as well until Ronny assures him his original team's deaths were not his fault.
Six months prior to the series, Andrew found a crown-like artifact called the Corona Aurora, but inadvertently freed two villainous brothers, Flurious and Moltor, from their imprisonment.
However, after Mack becomes involved against his wishes, Andrew reluctantly allows him to take his place on the team and uses his wealth and knowledge to provide support for the Rangers.
After Andrew Hartford finds the Corona and inadvertently frees the villains, the Sentinel Knight tasks him with helping him protect the artifact and retrieve the jewels due to losing his physical form.
[23] Additionally, following modifications carried out by Rose Ortiz, he gains the ability to transform into Battlizer armor for Mack Hartford.
Renewing his quest for the artifact, Flurious returns to Earth, takes over Norg's cave to establish it as a base for himself, creates monsters called "Chillers" to serve as foot soldiers, invents advanced technology, and battles the Overdrive Rangers.
[7] Throughout the series, he forms temporary alliances with Moltor, among others, in an effort into manipulating them into helping him,[24][25][26][27][23] constructs two giant robots that the Overdrive Rangers ultimately destroy,[28][25] clashes with Thor,[29] and turns the Fearcats into cyborgs in the hopes that they will serve him, only to be betrayed by them.
Fighting off Flurious' Chillers, Norg rescues Vella and brings her to the Overdrive Rangers before taking up residence at Hartford Manor.
Miratrix is a warrior and mistress of disguise who loyally serves under Kamdor after he saved her life and assists him in his quest to take the Corona Aurora and its jewels for their own ends.
Sometime prior to the series, he was imprisoned in a jewel while saving Miratrix, who eventually frees him in the present so they can steal the Corona Aurora for their own ends.
[33] Throughout the series, he clashes with the Overdrive Rangers, develops a rivalry with Will Aston, viewing him as a worthy opponent, obtains two of the Corona Aurora's jewels before losing one, and mounts several failed attempts at acquiring the rest.
The Fearcats are a race of malicious, sadistic, and ruthless demonic, feline-themed extraterrestrials who willfully destroyed planets and their inhabitants to demonstrate their power, possess the ability to enlarge themselves, and previously encountered Tyzonn.
While the majority of them were imprisoned in a mirror-like artifact,[15] Mig and Cheetar travel to Earth to find the Corona Aurora and use its power to free them.
Undeterred, Cheetar dies fighting the Overdrive Rangers while Flurious uses his technology to transform Mig and Benglo into powerful cyborgs in the hopes that they would serve him.
The pair subsequently betray him, stealing his technology to build giant robots to renew their quest for the Corona until they are eventually killed by the Overdrive Rangers.