Dragon Emperor

Dragon Emperor (竜帝) is the father of the Platinum Dragon Lord, Tsaindorcus Vaision. He is also implied to be the one responsible for the appearance of Players from YGGDRASIL in the New World.

Personality
According to Tsaindorcus Vaision, his father's need for absolute power corrupted him.

Background
It seems the Dragon Emperor has a family of his own. This includes himself being the parent of Platinum Dragon Lord. Alongside his son, he was possibly alive five centuries ago during the era of the Eight Greed Kings back then. It's currently unknown whether he has survived through the extinction of dragons perpetrated by the group of players.

The Rule of Conspiracy Arc
When considering the possible threats that the Argland Council State can pose to the Slane Theocracy, the Slane Cardinals narrow such threat down to only Platinum Dragon Lord apart from the rest of his surviving kind. Among the councilors who are in control of the Argland Council State, Platinum Dragon Lord is the one that the Cardinals are most wary of due to the fact that he happens to be the child of the Dragon Emperor.

The Witch of the Falling Kingdom Arc
During Tsaindorcus's duel with the Sorcerer King, as Riku Aganeia he briefly mentioned that the source of all this strife was with his father and those that followed him.

Abilities and Powers
The Dragon Emperor is most likely very powerful in his own right as the Theocracy's Cardinals considers his son to be a big threat to the Theocracy because of him. Since his son could use Wild Magic, it is quite possible that he should be able to also cast it likewise.

Assuming from his position of strength, the author Maruyama had the Dragon Emperor ranked #1 above the other inhabitants in the New World as it was measured by based levels. However, whether he is the strongest or not remains to be seen as not every True Dragon Lord and Zesshi Zetsumei were taken into account in Maruyama's ranking.

Nonetheless, his based levels are above the Elder Coffin Dragon Lord. As Cure Elim Los Malvar is ranked below him, this highly suggests that the Dragon Emperor himself is higher in levels than that level 95 Dragon Lord.

Platinum Dragon Lord
According to the Cardinals from the Theocracy, they classified Platinum Dragon Lord as the Dragon Emperor's son.

Although their exact relationship is unknown, The Platinum Dragon Lord is shown to have a very low opinion of his father due to his reckless and destructive actions that have continued to endanger the New World. This in turn has seemingly affected the Platinum Dragon Lord's mentality on powerful beings and cementing his belief that "Absolute power corrupts absolutely" due to his father's actions.

Dragon Lords
As seen with Cure Elim Los Malvar and Tsaindorcus Vaision, it's likely that many of his fellow Dragon Lords either possess outright hatred and contempt for the Dragon Emperor or a very low, pathetic opinion of him due to him being the one responsible for first bringing the YGGDRASIL Players into the New World and spelling the end of the Dragons' dominance over the world and whose influence with Tier Magic corrupted and degraded their own Wild Magic that has almost rendered the power useless.

Trivia

 * Its been stated by Cure Elim Los Malvar that Players such as Suzuki Satoru are the "Filth of the Dragon Emperor," implying that the Dragon Emperor had something to do with the continued appearance and transportation of YGGDRASIL Players to the New World.
 * And later his own son, Tsaindorcus Vaision during his duel against Ainz Ooal Gown also implied and confirmed that the situation of the continued transportation of Players to the New World was indeed the doing of his own father.
 * Though it's unknown why this drags the mind of the Players along with their avatars; but it's more than likely the resulted in brain death in World of 2138 for their human selves.