system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Who is the strongest witch or wizard to ever go to Hogwarts? Not most accomplished or famous, just has the greatest mastery of magic.
gpt
The strongest Hogwarts grad that we see in the series is Albus Dumbledore. In second place is Tom Riddle/Lord Voldemort. 

Characters whose power levels we don’t actually see but were likely very high are the original founders and Merlin.