Complex sentence: Willard H. Wright, who uncovers several truths behind the legend of the Golden Witch including Beatrice's true identity, of Yasu, the source of everything presented thus far.
Split into simpler sentences: Willard H. Wright, who uncovers several truths behind the legend of the Golden Witch including Beatrice's true identity. The other is Yasu, who is the source of everything presented thus far.