I call bullshit on all those wooden knives. Unless he went against someone in the past who had a similar ability there's no reason to prepare that many knives. And I doubt he has a storage item. Where would he keep them? And at a detriment to other weapons or items he could possibly need. What if his opponent was a wood bender or immune to wood? I see no normal way for this situation, unless he knew MC has this ability in advance of the battle.