User blog comment:Mathmagician/Wyvern Solo Walkthrough/@comment-4665212-20120105143043

One accessory that I found was quite helpful while fighting the Wyvern was the Cross Necklace. Seeing as the Cross Necklace nearly doubles the length of invulnerability after being hit, the Wyvern will only have the chance to hit you once or twice per fly-by (should he hit you at all).

Ps: Really nice guide, I just wanted to add =)