When the war ended, the demons returned to their dimension and the portals were sealed. One day, Dio realized there was a weakening of the magic sealing off one of the portals and decided to go and investigate. This decision set him on the road to one day meeting the knights of the Grand Chase.
Dio has a great sense of pride and takes matters from a selfish perspective in a serious manner. Such actions are hard to understand from a human point of view, but it is easier to comprehend if one thinks of him to have a completely opposite perspective from normal human moral standards.
Action Point System
Unlike every other playable character, the demons have a function called Action Point (or Ability Power) that masks over skills and some regular attacks, basically replacing Mana Points. Utilizing the Skill Tree, these characters are capable of using up to five different abilities, whether it be lethal skills or simple techniques. Unlike MP, AP skills and techniques are activated through the press of a button, rather than charging up to use a skill.
On the bottom center of the screen, the five skills will light up. This means that they are ready for use. The command interface with AP uses , , , , and . However, this makes Pet Attack left Shift and Taunt to .
Unlike others, AP characters do not gain newfound energy by hitting enemies but rather waiting out. However, since it is still technically Mana-based, it will absorb Mana fluids from potions, items, and armor properties.
Whenever Dio receives a counterattack, all the abilities get a 10-second cooldown at max. This can be reduced by a few seconds via Reduced Counterattack Cooldown Time, though not all AP characters possess this.
When AP characters advance further, they grow stronger and more lethal. However, they are unable to revert back to previous jobs as all of them are technically combined. They can use later job abilities while keeping their previous ones as well.
Dio can be unlocked by purchasing a Mission scroll from the shop and completing its objectives.
"Oh, how do I start. He is the most popular figure of the Demon World. Though he cannot return to his home. But should he return, are you ready to welcome him back?"
When unlocking Dio, he will automatically be at Lv.30 and is the only character to have such a head start.
During his childhood, Dio was a crybaby and often bullied by other Asmodians of his age.
In the Relics of Kounat, Dio mentioned that he has been pursuing "private interests" to which remained unknown.
Contrary to popular belief, it was not Dio who nearly killed Sieghart and the image of them fighting was actually a promotional artwork for the 'Sudden Death' PvP mode of the game. Furthermore, the chronological table of Grand Chase history did not mention this event ever happening.
In Grand Chase Dimensional Chaser, however, the incident was referenced in the expressions of Sieghart suggesting that it truly occurred albeit not in the way it was initially interpreted.
The background of Dio varies from each server of Grand Chase.
In Korea and North America, it was said that Dio came to Aernas.
In Brazil, it was said that Dio was trapped in Aernas and decided to oversee the portals to make sure they were sealed due to his pride and arrogance.
In Taiwan, it is said that Dio was trapped in Aernas and sealed his powers away, sleeping for a thousand years in a void between the two dimensions to stand guard over the borders.
In the Philippines, it was said that Dio was too strong to return to Elyos and had to seal his powers to get back.