Complex sentence: Later in May 2005, they recorded and released their promo "Rising of the Storm", which was then followed by their full-length self-titled debut album, released on April 13,2007.
Split into simpler sentences: Later in May 2005, they recorded and released their promo "Rising of the Storm". Which was then followed by their full-length self-titled debut album, which was released on April 13,2007.