When Lin Yuan contracted feys in the past, he had always contracted them at the Normal grade.
This was because he was lacking in spiritual energy and could not afford to be as free-handed with it as other spirit qi professionals were.
Some spirit qi professionals directly formed contracts with Gold and Platinum grade feys just because the fey appealed to them. Lin Yuan could never think of doing something so thriftless.
But after consuming many of the Cinnabar Osmanthus Haworthia's fruits and tea brewed from the Golden Thearch Bamboo's leaves, Lin Yuan's spiritual energy had been raised significantly.
He would have no issue contracting a Bronze fey.
Frankly, Lin Yuan could have used other methods to contract the Merciful Star Peony. If he used Morbius' exclusive skill, he would spirit-lock the Merciful Star Peony and form a contract with it.
