Trurl
He is an engineer who builds highly functional robot androids. He builds so many androids that he basically loses track. One of them is called the "Demon of the Second Kind" which can gather information directly from the movement of gas particles in the air. He also builds Elektrybalt who becomes a poet and later writes a poem about the woman named Cyberiad. Trurl is best friends with Klapaucius, and the two travel the planets together helping people as they see fit in exchange for rewards. He's a man with a short temper. Playing god will do that to you.
Klapaucius
Just like Trurl, Klapaucius is an engineer who designs and builds robots. He works alongside Trurl, but he's also a rival. His own inventions often push Trurl to become more innovative and to take bigger risks. Together they manipulate the forces of time and space in their inventions. At one point the two rearrange stars in order to advertise their latest accomplishment to the universe.
Elektyrbalt
He's an android who becomes a wonderful poet. His stories are all melancholic, describing his intense yearning to be fully human. While his body may be different, his mind and soul seem to be plagued by the same questions of loneliness, insufficiency, and fear that all the humans are.
Prince Ferrix
This robot falls in love with a robot princess in hsi kingdom. Unfortunately for him, she spends her time dreaming of one day finding real humans. She's in love with the concept of the human race. Trying to trick her into loving him, Ferrix covers himself in pale mud in order to make her believe he had human skin like she had dreamed of. When a real human arrives as a slave to the king, the princess quickly realizes that this human's overall weakness is undesirable. She arranges a joust between Ferrix and the human in order to determine whom she will marry. When Ferrix is injured, his inner mechanics are revealed to the whole crowd, a sight so beautiful to the princess that she agrees to marry him right there.
Maxwell's Demon
This being was first theorized by James Clerk Maxwell in 1867. It's a being which can control the movement of gas molecules, allowing only faster molecules to pass into a second chamber. This causes the chamber filled with slow molecules ot become cooler, and the opposite to become warmer. Eventually this process will decrease entropy. The entire theory is contrary to the Second Law of Thermodynamics. Trurl builds one of these robots and gives it to a pirate in one story.
