The answer is
When I was a young adult, I left something at level 2 because
He left the college at second year.
I found something, the thing I found is like a magnet to some people.
He is the founder of facebook. Many people are highly addicted to it.
Some say it belongs to the castle near the neck and the iron island.
The castle near the neck and the iron island is 'The Twin'. The twin brothers claimed that the idea of facebook belonged to them.
Use the map.: Use the map of Game of Thrones which helps in finding the name of the castle.
The answer has some relationship with him. Which person does these pictures represents? picture of [Batman v/s Superman + Lex Luthor]: As dmg correctly guessed, the character of Lex Luthor is played by Jesse Eisenberg who also played the character of Mark Zuckerberg in the movie 'The Social Network'.
If this question remain unsolved until 6-Feb then I'll post the answer myself. And I am sure you'll say "Oh f*k, that was easy."
Sorry for not giving it as hint but it was also a little hint. Here f*k = facebook And also sorry for revealing the answer a day earlier but I don't like puzzles to remain unsolved. One thing I would like to state is that today facebook has completed 12 years. :)