The ruler of the Gogol Empire, which is at war with the Jaicro Empire for control of the universe. He sends Dr. Gel to capture Dandy, claiming he is the key to the future of the universe. His appearance is that of a skull with miniature "planets" orbiting it. (Source: Wikipedia)
The newest experimental maid robot from Kurusugawa Electronics, driven by software called 'Dynamic Intelligence Architecture' designed by Sango. The body is customized from the mass-produced HMX-16 'Leon'. Ilfa proposes to work at Sango and Ruri's house during her testing phase which angers Ruri because she takes all her jobs. Even though she is hated by Ruri, Ilfa loves her because Ruri is the one who shows her that the outside world is not frightening. In the anime OVA, Ilfa is asked to serve at Yūji's house because he has a maid gynoid fetish which becomes a learning experience for her thanks to Tamaki. -Wikipedia-
Lucy is an alien girl who doesn't have much expression and doesn't have any friends. In the anime, she introduces herself to Takaki's class as 'Ruuko Kirei na Sora', which means 'beautiful sky.' She meets Takaki in the sixth episode of the anime, but we see her in an earlier episode without any dialog. She refers to herself as 'Ru', the name of her home planet and the beings on it, and to earth and earthlings as 'Uu'. She greets people by reaching for the sky and saying, 'Ru!' Himeyuri Sango in particular enjoys mimicking Lucy's greeting. Lucy has a cat that almost drowns in the sixth episode but it is saved with the help of Takaaki; Lucy summons a thunderbolt which splits a tree, forming a bridge which Takaaki crosses to lift the cat out of a raging river. Lucy terms this stray cat 'the Nya', saying that it is a special species that can enjoy the true taste of food, and like Ru, Nya is alone on Uu. Lucy likes to cook the Nya fish broiled over a charcoal clay pot, which according to her is the best cooking device available on Uu. Apparently a currency of Ru is matchsticks, one of which is enough to buy a whole rocket engine. Lucy irritates the cafeteria cook of Takaaki's school by attempting to treat Takaaki to the best meal the cook can prepare by paying the cook first one, then two matchsticks, however Lucy is somehow able to successfully purchase her charcoal clay pot and fish to br with matchsticks. Lucy says that on Ru, it is said that the only good Uu is a dead Uu, but Takaaki is a special Uu.
Tamo-san is Gintama's version of the real-life Japanese comedian Tamori-san.
Chaos is the king of the country of Tao. He has god-like powers and a fan made up of Sakura's memory feathers. He is actually completely made up of feathers.
Appears in "The Big Fish is Huge, Baby."