The crystal wyverns are a smart race. They cannot fall for the usual tranq-and-feed, instead opting for a passive taming, which is difficult upon itself. Fortunately, you can grapple to these creatures, without harming them, mind you, and feed them that way. But, being intelligent, they have elected a leader, and said leader is none too pleased about her soldiers being taken from her. If you dare challenge this leader, she will send hostile Wyvern soldiers to fight for her, but even the toughest leaders can be brought down. If you defeat her, she drops vast amounts of meat and Primal Crystal, an organic form of Crystal which unfortunately appears to spoil. The boss will be tough. Be warned.