Complex sentence: From 2002 to 2003, Grell worked on "Iron Man"; it was during a Grell written story from this period that Tony Stark revealed his secret identity to the world, a development met with mixed fan reaction.
Split into simpler sentences: From 2002 to 2003, Grell worked on "Iron Man". It was during a Grell written story from this period that Tony Stark revealed his secret identity to the world, a development met with mixed fan reaction.