Mag Mel is the mysterious masked entity who haunts Dan's darkest dreams and often appears to him as a vision, especially during a battle. Also, he has Anubias and Sellon as his primary brawler servants. It is unknown if he has any other servants, except for the brainwashed brawlers using his Chaos Bakugan.
In all his appearances, he's seen being next to Razenoid seated in a throne and they seem to be restrained by some sort of webbing.
In Interspace Showdown, He appears alongside Razenoid when Drago is battling and appears in Dan's nightmare and tells Dan to surrender Drago's powers to him so that he can be free. At the end of the episode he says "Dan and Drago have what I need. I need more energy. I need more power!!"
In Mechtogan Mayhem, He states that he and Razenoid are in captivity of some sort, as evident by the web restraining them. Near the end of the episode Sellon informs him that Titanium Dragonoid "spawned" a Mechtogan (Zenthon) and he was really surprised. He also then realizes that his powers are more powerful than he realized.
In Fall From Grace, He comments that the energy he needs from Titanium Dragonoid is starting to flow and he then orders his "Dark Servants" which are Razenoid's Chaos Bakugan to awaken.
In Agony of Defeat, He appeared with Razenoid when Dan was battling Anubias in a vision. These visions caused Dan to think that Anubias was Mag Mel and Drago to think that Horridian was Razenoid to the point where he lost control of his powers again and nearly killed Anubias. In this episode gained a lot of Chaos Energy from Titanium Dragonoid.
In Return to New Vestroia, He appears in Dan and Drago's vision and makes them pass out. He also finds out where they are with the closing comment "I can't believe that we found them in New Vestroia of all places!"
In Chaos Control, He makes Razenoid create another Chaos Bakugan (Darkus Iron Dragonoid) and he gave it to Anubias. He also gave him a Mechtogan (Venexus) as a gift and told him to go to New Vestroia to battle Dan and Drago. Later when Titanium Dragonoid gets control of his powers he and Razenoid lose their connection with Dan and Drago and are wondering how they did it. At the end of the episode he comments that both Dan and Drago have grown much since returning to New Vestroia and that they have to more to offer him that he could possibly imagine.
In A Royale Pain, He appeared when Taylean spawned a Mechtogan (Silent Strike) and absorbed all the Chaos Energy from the battle that they were in and he also said that soon he will be free to Razenoid.
Mag Mel has a Diamond on his armor that has striking resemblance to the one Drago has to represent thePerfect Core.
Mag Mel has a stronger bond with Dan when he is in the real world. This is proven in the episode Return to New Vestroia where Drago almost passes out after Mag Mel's vision. It can also mean that he's trapped somewhere in New Vestroia but this is speculation.
Due to him reacting to Dan being in New Vestroia of all places, it sounds like he has been to New Vestroia before, which could mean Mag Mel is a Vestal. It could also explain why his Chaos Bakugan resemble those of Bakugan from Bakugan: New Vestroia like Percival and Ingram. However, this is just speculation, but it is possible.
His voice and appearance are similar to the Highbreed, a villain on the Ben 10: Alien Force series.
Mag Mel is supposedly the first Brawler in the anime to have a Mechtogan Titan.
When he talked to Dan in Agony of Defeat, he claims to: "Share a bond that you cannot escape, no matter how hard you try." This may mean he has had a relationship with Dan and Drago from every season up until this point and he's possibly behind everything that has happened, but this is speculation. Just like Naga who is also the possible main villain of the series.
Mag Mel is the third masked brawler after Masquerade and Spectra.
A theory states that he is Gundalian showing how he got a hold of Anubias and Sellon, a double Neathian agent.
It's possible that Mag Mel cares very little for his servants and is just using them to get what he wants, as he was more then willing to put Anubias in danger in Agony of Defeat and all in order to get Dan and Drago to use their powers'.
It seems that he and Razenoid need a lot of Chaos Energy in order to be resurrected because after ten episodes of battles, he has not obtained enough energy yet.
There have been rumors that Mag Mel is actually Emperor Barodius. However, this is probably incorrect when Wavern commented that Mag Mel and Razenoid seemed very familiar to her and she never saw Barodius or Dharak.