|This article is about a/an villain in Power Rangers Lightspeed Rescue.|
- "You have done the impossible...you've defeated the Mighty Diabolico! But be assured that Queen Bansheera will avenge my defeat a THOUSANDFOLD!!"
- ―Diabolico's last words before being destroyed for the first time.[src]
A short time after the demons were released, Diabolico appeared before Captain Mitchell and his two children when they were hanging off the edge of a cliff after a car accident. Ryan was about to fall to his doom when Diabolico offered to save him, but in return, he asked for ownership over Ryan, to which Mitchell reluctantly agreed. After rescuing Ryan, Diabolico told Captain Mitchell that he would see his son again on his twentieth birthday. From then on, Diabolico trained Ryan to be a skilled warrior; this proved to be his downfall when Ryan switched sides.
Because of his repeated failures, Diabolico was threatened by Queen Bansheera, who wanted to take the Star Power and give it to her son, Impus. Diabolico considered even killing Impus himself to prevent him from having the Star Power taken away from him, but he lost the chance. Finally, after his Troika monster was destroyed, he made himself grow to try to destroy the Power Rangers. However, the Power Rangers formed the Lightspeed Solarzord and destroyed him by absorbing one of his blasts and using the power from it in their own cannons blasting him until he was destroyed. This was ironic, since the Rangers would not have been able to destroy Diabolico without Ryan's help as the Titanium Ranger. The Star Power drifted from the fiery explosion caused by his defeat and went to Impus, who matured into Olympius.
Diabolico was later revived (from what was said to be the Shadow World) by Vypra and Loki, who had almost been destroyed by Olympius and his monster servant, Vilevine. Diabolico immediately returned to his queen's side, attempting to regain favor with her and recapture the Star Power from Olympius. His plans went so far as to trap the naive demonic child in the Shadow World, where all dead monsters dwell. Queen Bansheera revealed that she knew what he had done but did not care about Olympius; she only cared about her plan to rebuild her palace.
After Bansheera absorbed Vypra to complete her metamorphosis into her true form, she briefly took control of Diabolico and forced him to fire at the Rangers. This ended up killing his ally and friend, Loki, who accidentally blocked Diabolico's shot. Diabolico has had enough. He turned against Bansheera, and told the Red Lightspeed Ranger where to strike to defeat her. Unfortunately for both Diabolico and the Rangers, she survived.
Fleeing Bansheera and no longer wanting to serve her, Diabolico was attacked and defeated by a vengeful Olympius. He was dragged back to Bansheera, who turned him into Olympius' mindless pet. The two then attacked the Rangers, but with the help of the Red Ranger (Carter), Diabolico's noble side came back out. He turned against Olympius once more, giving Carter the key to the Tomb. Olympius then took down Diabolico, and in response, the Rangers took down Olympius. Soon, Bansheera revived the two of them and made them into giant Super Demons, bringing Diabolico back under her control. They wreaked havoc on the city and the Rangers' Megazords. It took the power of the previously-unused Lifeforce Megazord to finally destroy the two Super Demons, at which point the key returned to the tomb.
At the very end of The Fate of Lightspeed, the Lightspeed Rangers fought Queen Bansheera in the Skull Cavern. Carter (the Red Ranger) knocked her inside, but she managed to drag him down, leaving them suspended above the monsters below. Carter urged his friends to close the tomb, but they didn't want him to fall in. At that moment, Diabolico's spirit appeared to help the Rangers. He freed Carter and dragged her into the Shadow World, exacting his final revenge on her. Carter climbed out and Ryan closed the tomb.
Despite being a villain, Diabolico cared deeply for his comrades, especially Loki. When he was forced to shoot Loki and destroyed him along with the Rangers, he ultimately defected from Queen Bansheera's side and ultimately became a short-lived ally of the Rangers. In the season finale, he was able to exact his revenge, helping the Rangers destroy Queen Bansheera once and for all.
Diabolico was evidently considered to be a good friend by Loki and Vypra as well as they both mourned him when he was killed by the Rangers. Even though he lied to Ryan to manipulate him, he did seem to care about Ryan and wanted him to rule by his side when the Rangers were destroyed. He even referred to him as Ryan during their time together. When Ryan solidify his loyalty to the Rangers over him, he stopped calling Ryan by his name and simply called him the Titanium Ranger.
Diabolico displayed strong spiritual powers, as he was able to appear in a spiritual form even when he was imprisoned and after being destroyed. He could also control the weather and summon energy blasts. In battle he used a skull-themed two-pronged staff with axe-like blades. He has also shown a strange ability where he can detach his right hand and grab onto opponents with it and bring the rest of his body closer to his target. With the Star Power, Diabolico was immensely powerful; one of his energy beams was enough to put a hole through the Super Train Megazord. Even without the Star Power, he was a competent fighter, nearly besting Olympius in their first battle. When turned into his Super Demon form, Diabolico was at his peak in power. In this form he used a jewel-encrusted sword as his weapon. When he combined his powers with those of Olympius, they were enough to destroy nearly all of the Rangers' Megazords, a feat very few villains and monsters are capable of achieving.
Despite being a villain, he was quite loyal to his servant, treating them more as friends. He never treated them as expendable pawns, especially Loki. He refused to fire on the Rangers when they were near Loki and betrayed Queen Bansheera after she forced him to.
- Diabolico's name is based on the word "diabolical," whose root comes from the Spanish word for "devil". "Diabolical" can also mean evil and underhanded, but this is in contrast to Diabolico, who has shown himself to be very loyal to those he believes in: initally Bansheera, and later Carter and the Lightspeed Rangers.
- Diabolico is the first major villain to help the rangers defeat another major villain. The second was Ransik.