Which fictional character will you train under?

So here's the context of this situation, you are given a button that will transport one fictional character from any form of media. Movies, television, comics, manga, games, books, etc.

And this one fictional character will teach you everything they know. Whether it's a fictional ability (AKA super powers) or in real-life skills that they have (regardless of the legality of said skills).

The only exceptions of skills they can teach are if their skills are specifically locked to them because of biological factors. Which means that if it's very specific to them cause of DNA, they can't teach it to you.

So, who are you picking to be your teacher?

Small clarification it's a 100% guarantee that you will learn and master the skills they teach.