As the show progresses in the second, third, and fourth seasons, it gets darker with the introduction of Donald's younger brother Douglas Davenport who later joins the Lab Rats' side, Douglas' android son, Marcus Davenport, Victor Krane, Taylor (formerly known as S-1), who joins the Lab Rats during the fourth season, Sebastian (formerly known as S-3), Krane's bionic soldiers, Giselle, who's planning on rebuilding Marcus, and Troy West, Giselle's android creation. At the end of the third season, Donald opens up a bionic academy on a bionic island to train Krane's bionic soldiers to be the world's new bionic heroes.