Johannes is a Rank V explorer and the strongest Thousand Voyager who oversees Satellite Base Theia.
Johannes is Al's future self. A short time before the Entity's arrival, he ends up in the Paradise of the current timeline. In the unfamiliar time and space, he was taken in by Mariv, who eventually marries him. Together, they have a daughter named Elroux.
When the Entity arrives and threatens to destroy Marble Blue, a man named Dufti, who is presumably acquainted with the family, tells Mariv and Alfred that they need to use Elroux to channel the power of the planet against the Entity. Mariv and Alfred refuse to hand their daughter, though both are subjugated by Dufti's men, leading to their daughter's capture.
The Entity turns out to have come to Marble Blue not to destroy it, but only to lay its egg on it. During the Entity's catastrophe, Alfred and his family gain the planet's power to survive on Satellite Base Theia. Mariv is mutated into an Incarnatus, though she manages to retain her sentience and has since lived under the Geofront Elevator, watching over the Entity's child, while creating a supernatural garden for Elroux, who lost all of her memories, to live. Alfred, meanwhile, takes on the alias 'Johannes' and becomes an explorer. He frequently visits his daughter, though he never reveals to her he's her father.
Over time, Johannes becomes a Thousand Voyager and is widely thought to be the greatest explorer in history. Since even his colleagues see him very rarely, it is said that when Johannes does appear, a great change in the world is about to occur.
Johannes is later seen participating in the Chancellor's Cup. As is expected, he easily defeats all opposition, including fellow Rank V Explorer Erik, to go into the finals and face the Protagonist, Leary and Elroux.
Johannes easily overwhelms the Protagonist's team and warns them their lives will be forfeit if they don't have the power to defeat him the next time they face him during their quest for Paradise. However, before he can proclaim victory, Volhelm sends Incarnati to attack New Paleo, forcing both him and the Protagonist's team to see to its defence. Johannes helps the Protagonist and his counterpart in this timeline to defeat Axiom, but then does not come back to the Modern Colosseum. As a result, the Protagonist's team are declared the winners.
After the entrance to Primordia is opened, Johannes shows up at the Edge of the World and meet up with the Protagonist and Elroux just after they are separated from the rest of the team. He accompanies them in the ruined city, eventually finding them being surrounded by Incarnati. Johannes helps them take care of the Incarnati before revealing to Elroux he's her father and walking into the central complex.
When the team later finds Johannes inside the central complex, he explains the bright light inside it is Marble Blue's well of souls, where the dead returns and is reborn. He challenges the team to a battle, and after being defeated, steps aside and lets Elroux and the Protagonist enter, where the Protagonist witnesses all what happened to Elroux in Paradise 1000 years ago.
Johannes later comes to the bottom of Theia via Theia's Nerve Center, where he finds the Child has managed to overpower and corrupt Mariv. He kills Mariv and engages in battle with the Child. Although he is overpowered, he sustains himself via sheer willpower and continues to hold it off before the Protagonist's team arrives.
Johannes dies shortly after the team appears, his memories becoming a Gene to continue helping them against the enemy.