Complex sentence: They laught along with Vulkanus after he mocks Rath's appearance, they appear to laugh because Vulkanus laught first as they only laugh as Vulkanus looks at them.
Split into simpler sentences: They laught along with Vulkanus after he mocks Rath's appearance. However, they appear to laugh because Vulkanus laught first as they only laugh after Vulkanus looks at them.