Complex sentence: The album is the last to feature guitarist Corey Steger and is the first to include keyboardist, Christopher Dudley as well as the first Underoath album to feature keyboard effects.
Split into simpler sentences: The album is the last to feature guitarist Corey Steger and is the first to include keyboardist, Christopher Dudley. Being the first album is feature Christopher Dudley, it is the first Underoath album to include keyboard effects.