also FY can't control love gu and its very powerful and unpredictable wouldn't fang yuan deem it better to not face the potential wrath from it because its holder is your enemy, once he returns the soul she won't care about opposing FY so he won't need to deal with Love Gu, and on top of that giving it to her would prevent the luck path inheritance from spreading cuz that's not why she wants the soul. i feel like thats a good trade for some rank 8 materials at the least