Fleuri Jodeau
So, this thing changes as it's damaged, Fleuri noted as he evaded the biting maw created by his blow. This would make it more difficult to attack any spot twice, and meant that this monster would get more dangerous as it sustained more wounds.
According to Fanilly, the wooden serpent was animated by a heart. Even stranger was Tyaethe's assessment- the heart was moving around inside the creature. The path forward was clear to Fleuri- they needed to tear up the exterior so that the heart would have no place to hide. Even if the creature could bite and snap from every wound, the key to killing it was taking out the heart.
Fleuri heard Fionn's request to drive the snake towards him. He wasn't sure of the man's plan, but trusted in whatever it might be. Fleuri swung at the snake's wound-maw, keeping just enough distance to strike the bark with the tip of his sword. He didn't need to maim it, just to encourage i to continue snapping and lunging towards him, and in doing so, should move the entire beast bit by bit in Fionn's direction.
Fleuri was curious to see just what Fionn had in store for this thing...