Okay so King Woodsie is 331,105,611,600 Joules while Marcy appears to be about 240,127,503,754 Joules, which gives Woodsie about a 1.3x AP advantage, which is pretty negligible. However since King Woodsie is fighting alone, its very in-character for it to start with 'Lone Force', tripling its damage output, giving King Woodsie about a 4.1x AP advantage after that, which is much more worrisome for Marcy. Lone Force specifically doesn't boost DEF though, so it's still only a 1.3x dura advantage.
King Woodsie is specifically weak to fire damage, so Marcy can rack some extra damage with her Fire Arrows too, however in PAD explosive damage doesn't interact with elemental weaknesses, so unsure if the Explosive Potion would do extra damage here or not.
They both have 'instant wincons' too. King Woodsie's 'Balance Enhancement' is an attack that should be a oneshot if it lands, meanwhile the Stinkshrooms dura negging could be a wincon as well, but the description does make it seem harder to use since King Woodsie would need to breath a certain amount in before it works?
Range is a non-issue, the starting distance is within both of their ranged attacks, and King Woodsie doesn't have evidence of attempting to flee to make use of its larger max range, and likely lacks the mobility to even try that. Speaking of, while they can obvious range each other, Marcy's mobility might be better thanks to her acrobatics? King Woodsie is only shown floating, and not flying in a greater capacity.
The Smoke Arrows don't have a full description, but I assume they put down a smoke screen? Good for keeping the advantage on avoiding hits for Marcy.
King Woodsie on the other hand has better defensive options it seems, with the capacity to heal itself and make forcefields to block incoming attacks. So while its durability isn't that far ahead of Marcy, it might be harder to take down than first expected.
Marcy is absolutely more intelligent, and possibly more skilled. Hard to say since King Woodsies are decent threats to Dragon Tamers, and like all PAD monsters seem to be capable fighters just naturally, but otherwise they're not really remarkable with big feats lists. Marcy likely edges out no matter how generous you are to King Woodsie, but they're no pushover either in a fight.
The real concern for Marcy is Woodsie's sheer damage output. 'Balance Enhancement's likely a oneshot if it lands, and even if it doesn't the temporary damage boost afterwards might still mean any normal attack will be a devastating amount of damage. Orb Combos will increase that 4x AP advantage even further, and the Mass Attack's AOE might be hard to dodge ontop of that. And 'Chow Time!' will inflict a bind on Marcy, making her a sitting duck and punching bag for those heavy hits.
I feel I don't know nearly enough about Marcy, especially skill feats, but for now I'm leaning King Woodsie for their defensive advantages making them hard to take down quickly, Stinkshrooms seeming to be a slow durability negation rather than a quick wincon, and King Woodsie's hefty AP advantage and ability to restrict Marcy's movement if they land and a Mass Attack that's almost certainly going to land if they use it.
