For the matters here, Du You spent several years entirely. First, he used his own flames to dissolve the core of the Flame Demon. This item, having already been tempered into an Origin weapon, could not be absorbed.
The dissolved core, Du You transformed it into a sphere burning with Soul Devouring Demon Flame, though its future use was unknown.
As long as this item wasn't reclaimed and reforged by that Flame Demon, it was fine.
As for that worm-like entity, Du You refined it into a unique cup, unexpectedly granting it new abilities.
The cup could produce a liquid every day, one drink of which could restore one's injuries, and even affect tier-nine powerhouses. This type of healing Divine Artifact was considered the highest caliber.
Du You himself hadn't anticipated such an outcome. And that muddle-headed guy, even if he got this item back, probably wouldn't restore it to its original state, meaning he would have a flaw for life.
