Estren's past is unknown. He and his older brother, Alphonse, were both human once, but were converted into Cards by The Game Master. Estren became a Club while his brother became a Spade (eventually reaching Ace status).
During the Tournament arc of A New Fear Will Soon Be Born, Estren was attacked in his store by a contestant, but was saved by Benjamin Malkator. Estren then began travelling with Malkator for a little while, until his shop could be repaired. Later, when Malkator became corrupted by HELLFIRE, Estren fought against him to try and get Malkator back to his senses. During the fight, Malkator managed to overcome HELLFIRE long enough to give Estren his current sword, a cutlass. Estren then used his power to tear HELLFIRE out of Malkator's body and into his own, which he did to repay Malkator for saving him before. Throughout the rest of the tournament, Estren drops off the radar, trying to keep HELLFIRE under control. Eventually the two of them come to an agreement in which HELLFIRE would help Estren to resist the Game Master and earn his freedom from The Board. The two of them teamed up with Malkator, The Crow, O'Zalia, Ren, the Samurai, and Quan in the fight against the Game Master. Although the battle was lost, Estren managed to escape along with Ren through The Crumbling Castle.
Estren began his own blog and continued to keep HELLFIRE in line. He began helping HELLFIRE search for the legendary Godslayer by stealing the diary of Garrot Kelterry and tried to figure out where it was hidden. Estren eventually teamed up with Malkator once again, as the Game Master's plans continued. The Game Master sent an Emissary named Amy to defeat Malkator, and Estren engaged her in a poker game with his mask on the line. He defeated her, and she agreed to quit working for the Game Master and join him as his personal servant.
He continued to stand against the Game Master and his forces, which culminated in an Emissary known as the Scientist stealing HELLFIRE from him. During his hunt for the Scientist, he discovered the Game Master's plan to use an eldritch bomb to commit mass genocide on humanity, making Estren a major liability. The Game Master attempted to strike him down, but Alphonse betrayed him and took the hit instead in order to save Estren. This resulted in his mask being broken and cursed, but fortunately didn't kill him. Estren got Alphonse to safety, and had Amy take care of him while he set off to finish things and get HELLFIRE back. The Game Master's plan to destroy the world was foiled by Malkator's sacrifice, and Estren managed to get HELLFIRE back using a spell Alphonse had given him before he left. Afterwards, he and HELLFIRE continued their search for the Godslayer.
Estren's mask received a mysterious upgrade, which allowed him to locate and unfreeze Garrot Kelterry, but his memories had been erased. They put their search for the Godslayer on hold in order to deal with Silvermist, a rogue Dying Man shard that was once part of HELLFIRE. But when Silvermist proved too strong for them, they decided to try and achieve unison by training in The River. When Silvermist came to confront them, HELLFIRE and Estren fused into Infernal and managed to defeat and consume her. They then decided to stop blogging.
Estren is a debt repayer; he will do what he can to help people who have done something for him in the past. He is protective of his friends and brother, and is often at odds with HELLFIRE's violent mannerisms. He is also a pervert, which is pointed out on numerous occasions.
Estren's main weapon is the cutlass given to him by Malkator. He also has his Game Mask, which can pull up data on humans, access the internet, and transform into a shield. After the Game Master's death, his mask ends up getting an upgrade, improving its functions and adding new ones. Its shield form was replaced by a gauntlet that projects a force field.
In addition to the powers he gains from HELLFIRE, Estren has some abilities of his own, which come with being a Club.
- Teleportation: HELLFIRE can teleport virtually anywhere, but can't cross into other domains with this power. If he's in a domain, he can only teleport to other parts of that domain.
- Quick Thinking: Estren can think faster than most people, and can solve complex equations in his head without even having to use his mask.
- Possessive being removal: A trait shared by all Cards, that allows him to tear possessive beings like Dying Man shards out of people and into himself. He can also resist their control to an extent.
- Agelessness: Estren's body can't age, but his hair and nails still grow as normal. He also can't have his body decayed by Dying Man shards.
- Luck: Apparently, all Cards have really good luck.
- Union: While in The River, Estren and HELLFIRE can fuse their souls together, becoming Infernal, who has all their powers cranked up to 11.