Complex sentence: He then appears to aid Weretiger for battling two magicians as he decides to battle Wizard while Weretiger battles Beast, and he also uses Shunpei as his hostage.
Split into simpler sentences: He then appears to aid Weretiger for battling two magicians as he decides to battle Wizard, while Weretiger battles Beast. Not only that, he also uses Shunpei as his hostage.