Complex sentence: Iron Man 2020 (real name Arno Stark, Sr.) is a fictional character, a superhero appearing as the counterpart of the superhero Iron Man in the future year of 2020 in the Marvel Comics multiverse.
Split into simpler sentences: Iron Man 2020 (real name Arno Stark) is a fictional superhero. He is the counterpart of the superhero Iron Man in the future year of 2020 in the Marvel Comics multiverse.