Gustav wears a dark green suit over a lighter green shirt and a yellow tie. He also wears dark green trousers and dark brown shoes. He has white hair, a beard and a mustache, and has tan skin.
Gustav gives you the following puzzles in Professor Layton and the Miracle Mask:
Chapter 5: Miracles Unmasked
Professor Layton and the group meet Gustav at the racetrack, wanting to ask him questions in relation to the Masked Gentleman. He is asked if he noticed anything unusual before the petrification incident, however he says that things around the racetrack had been rather routine for a while. He also says none of the chariots were removed on that day, and lets Layton take a look at them. After looking at the chariots, Layton asks Gustav if it was ever necessary to remove the chariots from the racetrack, and he tells them they're only removed for maintenance, which are all signed by Henry Ledore. Layton takes a look at the maintenance records. He notices that one of the chariots was removed on the night of the petrification incident, and was signed by Henry. Gustav asks if it had a connection to the Masked Gentleman, but Layton tells him not to worry. Gustav also lets Layton know that he had missed the opportunity to speak to Henry by mere minutes, and had been investigating the incident on the previous night. A black cloth was found in the Gallery Plaza that was used to wrap the donations Henry had offered to the Montsarton Gallery, and so Layton and the group decide to stop by the Ledore Mansion to speak to him.
Chapter 7: The Reunion Inn
Gustav comments on how it was a fine day at the racetrack, and asks Professor Layton if he was there on a break, seeing as the investigation was exhausting. However he couldn't, as he had the underage Luke with him. Gustav had heard that Layton was good on a horse, and considered he should race some time, to which Layton would give some thoughts about.
In a special episode, Gustav is discussing with Drake and Pascal about their issues with Murphy, who has been discussing their confidential financial information to other people. Pascal recounted that Murphy had told a customer the hotel's profits of the last five years, and Gustav says how Mordy quoted his figures back to him. Drake suggests that they report him to Henry, but Pascal notes that he had helped Henry in building the Reunion Inn, and if it weren't for him, Monte d'Or wouldn't be where it currently was. Drake says that it was all in the past, and now that the city was well established, there wasn't anything going for him. At this point Murphy walks in to work on their accounts, and spills to them that Dalston had been doing well in the past month by investing in the One-Ring Circus.
Layton and the others meet Gustav back on the racetrack, and he still couldn't believe someone would take off with one of his chariots. Layton tells him it wouldn't be a petty criminal, as it would take someone with money, time, accomplices, and being familiar with the town. He hoped the criminal would be caught soon, and then gives him a puzzle. He didn't feel he could keep the racetrack open while the Masked Gentleman was still at large, and this was due to inadvertently creating an avenue for one of his miracles.
"Respectable Gustav may be getting on a bit, but he still commits himself to the proud pastime of horse racing by tending to the racecourse. If there's one thing he wants, it's to have his sport take the world by storm. It's just a shame nobody take his ideas seriously..."