When Vyse and company finally get across the Southern Sea, they find that their fuel supply has been drained. When they ask the natives, the Ixa'takans refuse to help them because they think that Vyse and company are just like the Valuans who had enslaved their people and killed off the people who protested. As they go around the village, they eventually find a ship that had crashed in Ixa'Taka. On the ship, they find Hans, who is a fellow Blue Rogue.
Drachma recognizes that the ship belongs to Centime the Tinkerer, a famous Blue Rogue. Centime is also known for adopting orphans and taking care of them. Hans confirms that yes, he is one of those orphans too. Aika asks Hans if they have any moonstones to spare since they ran out of fuel, so Hans says that they do and offers them some of his. After Hans gives them the moonstone, he tells them about how the Ixa'Takans are enslaved and sent to work in the Moonstone Mountains and that his father is also imprisoned there. He believes that his father is still alive, and has been trying to restore the ship ever since to get him back.
The next time Vyse sees Hans again is after they have rescued Centime and Isapa from the Moonstone Mountains. Hans is overjoyed and thanks them. Eventually, Hans will ask Vyse if he can join his crew, and it is up to the player whether they will accept or not. Chances are that they had better accept him as a crew member.
Hans is not a playable character, but he may serve a purpose in air ship combat and in the Blue Rogues Special S-move.
Hans can be recruited by talking to him before clearing Yafutoma first. He will ask Vyse if he can join the crew once he finishes his factory tour. Choose yes. After clearing Yafutoma, Hans will ask Vyse to make good on his promise and let him join his crew. No brainer, choose yes once more.
Hans can probably be recruited if the player did not talk to him before clearing Yafutoma. After clearing Yafutoma, Hans will probably ask Vyse if he can join the crew after finishing his factory tour, and then Vyse can either exit the village or the area and then talk with him again to recruit him. This method has been used by a couple players, but more evidence is probably needed to see if this is a viable method or not.
If Soltis has risen, then Hans won't be in Horteka anymore. Vyse will have to find the manufacturer and speak to him first.
In air ship combat, Hans' Crew Command is automatic. If he is in your active crew, then he will increase twenty magical defense to the ship which is opposite of the other engineer, Brabham, who will increase twenty regular defense to the ship if he is in your active crew. His position in the crew is "engineer", and he will the second engineer the player gets.
In the Blue Rogues Special S-move, smoke will cover the screen before Hans emerges with his machine revved up behind him as he declares "The Rejuvenator is ready!" Considering the name of his machine is the 'rejuvenator', his role in the Crew Command is that of a healer's.
Despite meeting Hans in the storyline like Marco and Moegi, Hans does not join the crew automatically. Hans frequently addresses Vyse as "Mister Vyse" even though he is fifteen years old and only two years younger than Vyse. Hans has a dream of being able to revive ships, and his hobby is making toys. After Hans joins Vyse's crew, Centime, Centime's wife, and Centime's other adopted orphans will tell Vyse to take care of Hans.
In the Crescent Island Base, Hans can be seen in the room underneath Vyse's and Enrique's room with Marco and Pinta. If he talks to Vyse, then Hans will talk about how he's learning so much from Brabham, the crew's older engineer, and apparently seems to respect him very much. In the ship, Hans can be seen in the main room supposedly operating a machine and tells Vyse about how powerful the Delphinus' engines are.
While Hans is usually very cheery and smiles often when talking about technology, after Valua bombs the Crescent Isle Base, and it is rebuilt, Hans will frown and tell Vyse that Valua's ships were really fast. It may be one of the only times Hans gets angry about something. Hans also has a habit of brushing his bangs back and raising his hand. At the end of the game, Hans will work in Valua with Brabham and marry Urala (the game does not even hint at their relationship, so it definitely comes as a surprise).