This isn't truly unlimited regeneration, but a form of overdraft.
Those golden flowers don't appear out of thin air; they consume Audric's Origin Power.
Every flower that blooms costs him a portion of that power.
He can use these flowers to heal his wounds, but every healing makes his strength that much weaker.
There's no way he can maintain this state forever; his Origin Power is finite.
Duke didn't know where that limit lay, but he knew that as long as he dragged this out, Audric would run dry sooner or later.
Duke shifted his strategy.
He stopped trying to wound Audric and focused instead on evasion and harassment.
His sand-flow roamed all over the battlefield, keeping Audric from locking onto his position.
The colossus no longer clashed head-on with the dragon, instead leveraging its speed to dart rapidly around the dragon, striking from different angles, then retreating at once.
