Could you please check these sentences? Thank you.
1) Prospero lost his dukedom because of a plot set up by his wicked brother Antonio together with the king of Naples.
2) Prospero is not native to the island.
3) Thanks to his magic art Prospero subdued (made slaves of/enslaved are possible??) all the spirits living on the island becoming the master of the island.
4) He then took two creatures into his service: Ariel and Caliban.
5) Prospero raised his daughter on the island, together with Caliban, a sort of monster half-man half-beast.
Commas needed in 1 and 3.
In 3, "... on the island becoming the master of the island." <~~sounds as if the island is becoming the master...
This is known as a misplaced or dangling modifier.
http://grammar.ccc.commnet.edu/grammar/modifiers.htm#danglers
Everything else is fine.
Sure, I can check these sentences for you! Here are the corrections and suggestions:
1) Prospero lost his dukedom because of a plot set up by his wicked brother, Antonio, together with the king of Naples. [This sentence is grammatically correct, but adding commas before and after "Antonio" helps improve readability.]
2) Prospero is not native to the island. [This sentence is grammatically correct.]
3) Thanks to his magical abilities, Prospero subdued all the spirits living on the island, making them his slaves or becoming their master. [Your original sentence is correct, but using "enslaved" instead of "made slaves of" in this context might sound better. Additionally, "subdued" means to bring under control or conquer.]
4) He then enlisted the help of two creatures: Ariel and Caliban. ["Enlisted the help of" conveys the idea that Prospero sought assistance from Ariel and Caliban.]
5) Prospero raised his daughter on the island, together with Caliban, a sort of monster who is half-man and half-beast. [Your original sentence is understandable, but to improve clarity, it's better to place the description of Caliban after stating his name.]
Overall, these sentences are well-written, and with these minor changes, they would sound even better! Keep up the good work!