((Apologies for taking so long to post.))
Mateo manages to cut through the first wave of pondweed, if sloppily. It's hard to build up enough momentum under water, so the tear is jagged and slow. But even though he manages to fend that much off, there's still much more behind it. The pondweed surges up out of the murky depths below, wrapping around Mateo's limbs and torso with surprising speed and agility.
The blades are quite interesting. The triplets can tell they're magic almost as soon as they pick them up, but right now the magic is weak. The swords have opposing energy, like aligning heads of magnets. The closer together they are, the weaker they are as well. Right now, they function as little more than swords - albeit very well-made swords. Each of them fits their grips perfectly and is weighted just so. Should the triplets experiment in taking the blades further apart, a small, blue flame will coat the blade once they're a good ten metres apart. As fire goes it's very weak, won't do much damage, and would probably get put out quite easily. But it stands to reason that the further apart the blades are, the more powerful the flame will grow.
Morty's hand passes right through the hand, touching his own shoulder. But it still remains there, super-imposed over his.
Hey, says a familiar voice, steeped in good-natured, although concerned, amusement. What are you doing down there?
Well. All of the horns seems like a bit of an overestimation. There's four rams, each with two. It's pretty hard to hit eight targets in direct succession, especially if they're all quite close to you and moving closer with alarming speed. Thenadier manages to cut off one ram's, sure, but his vorpal blade whiffs through condensed water for the rest. The flame is certainly much more effective, burning through the cloud-rams with remarkable speed. But since apparently it needs to be announced, the act of announcing it gives at least one or two time to crash into him. That's gonna hurt.
Speaking of things hurting! The description of Thenadier's fire is alliterative, but not helpful. The fire bursts out, yes, but thanks to the wonders of polearms Mercutio is standing quite far away. Does it reach quite far enough to singe the devil, or does the act of directing it upwards to the rams negate most of the threat? You didn't really describe how Mercutio's attack effects Thenadier, either, so I'm going to say that by leaning backwards all Matrix-style, Mercutio is able to complete his attack.