|“||Endure It! You owe me that much Casshern for I am only alive to FIGHT you! I was able to survive and now it is your turn to do the same!||”|
|Behind the Scenes|
|Debut||The Man who Killed the Sun Named Moon|
|Voiced By:||Jerry Jewell|
Dio (ディオ, Dio) is a robot built identical to Casshern in order to pro create alongside Leda. Dio's original existence was a failure and so he was then utilized for his extreme conditioning to be a killing machine for Braiking Boss' empire alongside Casshern. During their lifetime, Casshern was always one step ahead of Dio causing him to becoming continuously envious of him until the very day Casshern murdered Luna.
After the Ruin began due to Luna's death, Dio left Braiking Boss with Leda as they hunted for Casshern, Leda manipulated Dio into creating an army to once again rule the planet. Soon they found out about the rumors of Luna and used this as a chance to use her in order rule the world and end the Ruin. Even through all this Dio only wished for revenge against Casshern, above all else he only existed for violence.
Dio finally realized Leda's manipulation and freed himself from her grip allowing him to finally enact his revenge. In Dio's final battle with Casshern, his heart felt a burning passion that Leda's dreams of eternal life could never replicate, this passion allowed Dio to defeat Casshern in that moment he had always lived for. After fulfilling all his desires, Dio allowed the Ruin to claim his life after living it to its absolute fullest.
Physical AppearanceDio was built in the same shape as Casshern, their physical features such as their height, weight and structure are identical. This has caused many to confuse Dio for Casshern, even though he has several distinct features of his own. Dio has long silver hair that reaches past his shoulders and sapphire blue eyes, with a scar across the left one. He wears a dark violet full body suit with a large collar, spiked elbows and yellow designs. He also wears unknown devices on his hips and his matching violet helmet to its suit. It is very similar to Cassherns but a difference color as well as different horns and ear pieces, Dio broke off one of the horns purposely to distinct himself from Casshern. His helmet is also able to produce a mask like both Casshern and Leda's.
Dio is a heartless, passionate and cold man with a burning envious desire that matters to him over all else in the world. Dio was able to survive solely based on his drive to defeat Casshern, seemingly untouched by the ruin as proof of his convictions. This passion is what drives Dio to be the warrior he is, but at first this was an obsession that weakened him. After being defeated by Vulcan and Mars, Dio realized he had to convert this into his own life's desires in order to defeat them, and Casshern.
Dio also seems to be not easily manipulated or controlled as Leda has had to use several tactics in order to get him to do as she pleases, and even after many attempts Dio still left her. He was also loyal to Braiking Boss for many years but left after the start of the Ruin. Despite his hatred Dio has also proven to be loving, on his deathbed he wished for Leda to be safe, even after all she's done to him.
Dio was created by Braiking Boss' number one professor Ohji, he was built in a set of three alongside Casshern and Leda. He and Casshern created to pro-create robotic life with Leda, they were to become gods but ultimately failed. They were all then passed onto Braiking Boss for their superior structure to become the ultimate killing machines. Even though they were created identically, Casshern was always stronger then Dio due to his lack of restraint and sanity.
This caused Dio to become increasingly envious towards Casshern until the day that Braiking Boss gave the order to kill the Sun Named Moon. Dio and Casshern went together on this mission but Dio was betrayed and left behind by his superior who went on to kill Luna and become known as the worlds strongest, sending Dio to the boiling point. 
Dio used his rage and obsession to drive his body and life to prolong and survive the Ruin in himself, becoming almost completely unaffected by it. He survived until the day that Casshern would return to the world, living alongside his love, Leda. 
When Casshern made his return to the world, Dio found him in his uncontrollable rage, and revealed to Casshern that he was formerly a killing machine before he lost his memories. Dio also lies to him by saying he is stronger then Casshern and can stop the Ruin by killing him. The two fight but Dio is nearly defeated by Casshern's rage only to be saved by Leda and forced to retreat.Dio returned to his base of operations where he and Leda spread the word of his power in order to rally an army, under Leda's recommendation. Dio was not as interested in ruling the world but went along with it in order to prove his strength to all.
Unbeknown to him, The God of Death Dune had entered his ranks and was in battle with his lady Leda. Before she was defeated, Dio interrupted their duel and battle Dune himself. Dune enraged Dio by confusing him for Casshern, allowing his rage to best Dune without killing him. Dio used this experience to realize that he must make it known that he and Casshern are not one in the same, he spread his army far and wide in order to locate Casshern.
Once the rumors of Luna's return spread, Leda took an interest in finding her by using the army. Dio let this go as he had successfully located Casshern and was ready to confront him. His army proves no match for Casshern, giving Dio the change to prove his strength in the moment. The two battle once again but this time, Dio almost conceals victory until Casshern reveals he wishes to die. Unable to take in a proper victory, Dio refuses to kill Casshern and leaves the scene to wait for Casshern to realize what Dio desires.Led by the want to find Luna and become Queen, Leda uses Dio's army to find the Sun, this leads Dio and Leda to a lead where they encounter their former comrades, Vulcan and Mars. Dio has become an icon to robotic bandits everywhere as a capable leader, Vulcan and Mars wish to strip Dio of this title by defeating him in battle. Dio battles them for deceiving him but is defeated after proving no match for their combined strength.
Dio is forced to realize that his obsession is holding him back, this is where his former master returns. Braiking Boss confronts Dio forcing him to remember that Casshern was stronger before but Dio can become stronger now. Dio uses this to fill his passion and strength, allowing him to fight Vulcan and Mars once again, this time defeating the two and once again proving his strength.
Although Dio has proved his strength to the world, he is still unsatisfied and can only follow the lead of his lady Leda. The travel to Luna's birthplace in order to find her secrets but are denied by Casshern, who due to Leda's selfishness, Dio is unable to confront or battle him. 
But Dio would soon reclaim this chance as he and Leda locate Luna's healing grounds. Uninterested in Leda's wishes, Dio simply orders his army to attack, leaving Casshern to defend it. In a deep despair, Casshern does not defend himself and is defeated by the army, much to Dio's disappointment he captures Casshern and chains him in order to allow himself to heal, for their final battle.Leda tries to convince Dio that Casshern is defeated and they must seek eternal life, but Dio finishes with Leda's deception and leaves her side in order to get what he desires. He lays in wait for Casshern's revival, simply waiting for their final battle. Dio confronts Casshern and frees him in order to further the healing, telling Casshern that he owes him this battle for making Dio like this, someone with only one desire in the world. 
Casshern finally heals himself and prepares for their final battle. Their fight begins and Dio finally experiences the feeling of life within himself, one that he says can never be replicated by living forever. Dio is finally content with his life and is living it to its fullest by fighting against Casshern.
The two battle back and forth, but Dio simply has a real reason to fight, the moment for life that Casshern can never understand or replicate, this is why Dio is truly the strongest. Dio and Casshern land their final blows and Dio fatally strikes Casshern which would otherwise kill him, giving Dio the win he's always wanted.
This is what Dio has always wanted, he had defeated Casshern and live his life to its absolute fullest. He had to no longer worry about death, or his own limitations and not even his own fate. He allows the Ruin to take him and apon his final request to Casshern, he asks him to save Leda from herself, revealing that she was still important to him. Dio dies after experiencing true life that is remarked by Casshern as beautiful and because he still cared enough about Leda, before she died, she joined Dio in death, in peace.
Powers and Abilities
Master Combatant: Dio has proven himself to be the absolute strongest warrior in the world. He was built identical to Casshern and was held back by his sanity, causing him to become Casshern's second in strength. Dio strived to become stronger and survived the Ruin in order to reclaim his title. He is known throughout the Ruined World as the strongest next to Casshern, which caused a robotic army to rally behind him.On several occasions Dio was able to best Casshern but never truly got the victory he wanted.He learned that his obsession was not strong enough to power himself and he had to make it into his life passion, with this he was able to best the likes of Vulcan and Mars the former strongest robots in the empire. He continued with this and went on to his final confrontation with Casshern, he proved his strength and defeated his rival, with this he was granted the title of the worlds strongest warrior. 
- Master Hand to Hand Combatant: Dio has a high dexterity for close quarters combat using only his limbs to fight. He is extremely fast and uses his speed to attack his opponents quickly and overpower them with is incredible strength. He uses swift punches and kicks that are able to pierce and smash apart robots, including his signature kicked that he's used in a number of his battles.
Enhanced Physical Condition: Even after the start of the Ruin, Dio maintained conditioning of near perfection, able to match Casshern's unaffected body. Dio possess extreme speed, strength, durability and stamina and is even able to heal his wounds over time.
- Enhanced Strength: Dio possess incredible strength that is able to match Cassherns. He is able to easily crush the average robot and even pierce powerful robots such as Dune and Mars.He was also able to pierce the tough exterior of Casshern's body, giving Dio the win in their final bout. 
- Enhanced Durability: Dio possess a high resistance to damage against his body, even higher then that of Casshern. Although he is not immortal he is able to survive blows that would be otherwise lethal and even heal over time. 
- Enhanced Agility: Dio possess incredible speed as his main quality. He is fast if not faster then Casshern and is fast enough to move through the air and run on water. His speed can even be mistaken for teleportation in some cases, as he can move faster then the eye can see.
- (To Casshern) "You were created to annihilate all life yet you can save them if you sacrifice your own"
- (To Dune) "Your no different...all you see when you look at me is CASSHERN..I am not him!"
- (To Himself) "I do not believe in God or a higher power, but I am grateful for this blessing" 
- (To Casshern) "Do me one last favor...save her for me" 
- 05. The Man who Killed the Sun Named Moon
- 06. Reunited with Fate
- 10. The Man Entrapped by the Past
- 13. The Past Rises Before My Eyes
- 14. The Truth Illuminates the Darkness
- 16. For the Strength to Believe
- 17. The Glass Cradle
- 21. The Paradise of Lost Hope
- 22. A Drop Called Eternity
- 23. Those Who Return