Flop has long bangs and long cream blonde hair, which is the same colour as his sister. His eyes are a sky of blue colour, which compliment his pale skin rather well. He is also described as shorter than his sister Medium. Compared to her, Flop is also not physically strong.
Flop is extremely helpful to almost everyone he meets, as shown when he helps Subaru, Rem and Louis into the city of Guaral, and even helps them sell off the horn of the El Gina so that Subaru can fund his trip back home. When Subaru asks why he is helping him, Flop states that he wishes to make the world a better place, and to do that he needs to help as many people as he can. It is noted that many people in the city of Guaral owe Flop some favors because of all he has done for them.
He is also shown to be very caring for people, as shown when he rushes to the aid of a man who was thrown through a window, and when he tries to stop Subaru from giving away all his money to Rowan. He was also willing to sacrifice himself to save Subaru from Todd Fang when he was about to kill him.
Though not much is known about Flop's past, it was revealed that he and his sister Medium grew up in an orphanage in a small town called Averyk, where they were routinely beaten by adults. Due to the constant unjust treatment they've received as children, Flop and Medium have vowed to take revenge on the world.