Complex sentence: Corwin then agrees to aid Bleys in his attempts to assault Amber and defeat Eric and gathers a large group of warriors from Shadow and assembles a navy, while Bleys creates an army on land.
Split into simpler sentences: Corwin then agrees to aid Bleys in his attempt to assault Amber and defeat Eric. Corwin gathers a large group of warriors from Shadow and assembles a navy, while Bleys creates an army on land.