Mad Scientists found within the basement of Ratayu have a very brief albeit important role in Legend of Legaia. They manage the growth of the Juggernaut within the basement of Ratayu and prepare the Seru Bride for its absorption. It is highly likely that they were in control by Van Saryu and returned to normal after the Sim-Seru controlling Bon Saryu was destroyed.
The scientists are seen within the basement of Ratayu managing the machine used to control Juggernaut's incubation. They prepare Noa to be absorbed by Juggernaut after Saryu's guards immobilize her, however once Vahn and Gala come to her rescue they flee the scene. They are not seen after this at any point in the game.