The transformation necklace was a treasure from the Woolf royal family. Back in the old days, it was a magical item made to facilitate the family's members to travel through the Holy Continent. It was said that the orc god had to sacrifice a large amount to invite Great Druid, from the elves to complete the necklace together. Therefore it could only be used by the most important members of the Woolf family's younger generation.
The recovering spell of the transformation necklace was also inherited only by the Woolf family. Suddenly, Abel had realized that he didn't know the spell of how to recover back into a human. He only knew the spell of how to transform into a worgen. Luckily, these magic items would often contain information about it's using instructions within it. Therefore Abel could find the recovering spell by injecting his power of the Will.