Complex sentence: Finally, after 1 year, FT Island's returned to Korea in late September 2013, and released their member-composed mini-album' Thanks To' on September 23,2013, to reflect their thanks to all of the people who have supported them.
Split into simpler sentences: Finally, after 1 year, FT Island's long awaited comeback to Korea occurred in late September 2013. They released their member-composed mini-album' Thanks To' on September 23,2013, to reflect their thanks to all of the people who have supported them.