Harry Potter: Part Three

In the third Harry Potter movie (Prisoner of Azkaban), Sirius and Potter encountered many dementors by the lake. A deer patron saint appeared. Who was the patron saint? Sirius? Potter's?
In the last part of Book Seven, there is a conversation between Dumbledore and Snape. It says that Snape's Patronus is a deer. Is the Patronus that appears by the lake in Book Three Snape's?
Thank you for everyone's answers ~
P.S. Level-5 Magician on the 4th floor, I'm as confused about this part as you are about Snape's deer, but I will never ask you unreasonably and conceitedly, child, have you read Harry Potter?
HP fans should be confident, but overconfidence becomes arrogance. Have a good night ~

Answer 1

Hermione and Ron spend a year together at Hogwarts School of Witchcraft and Wizardry in Harry Potter III. During the year, they had experienced many adventures and made many friends. One of the most famous adventures was the decisive battle with Voldemort and his followers. Hermione and Ron played an important role in this battle and eventually defeated Voldemort. They had learned many magic skills and experienced many setbacks and difficulties in the process. What magical skills did Hermione and Ron learn in the third Harry Potter story?