"I meant no insult!" Dodge ball of lava. "I don't intend to interfere, you said no!" Dodge house-sized spear of ice. "I'm leaving peacefully, okay, so stop tearing up the tile!"
"You'll respawn at home. No permanent damage. You interrupted an important meeting, you need to learn a lesson about territory, mountain bitch." Dodge- no, fail to dodge a thrown tree, and then another ice ball. The next sphere of magma is what destroyed that form.
She wakes up, stripped of all her tools and enchantments and even clothes, and groans in pain.
Anyway. There's a creature, yes, though even the armor and the diamond visor don't make the torrential rains between her and it be any less blinding. The silhouette of a—something, thirty-feet tall, can be seen. And it's fast. It moves this way and that with blinding speed, even as tiny specks—flying people? Other Fates, perhaps?—fight against it with the strangest magic.
At no visible command from the giant creature, the water that's invaded the land starts receding.
She takes some solid hits, obviously. But that's what armor's for. Raw physical force alone isn't enough to break her. Yet.
The water that left is going to come back in a big wave. She keeps half a mind's eye on it, and dashes coastward to raise a tall and thick wall - directly through some former buildings - when it starts to come back. Breaking up the wave's momentum won't stop the area from flooding, but it will help.
The wave does come and hit the wall, and as expected its momentum is broken up—though not nearly as much as it by rights ought to have been. The beast looks at it for a second and then—vanishes.
A ridiculously fast trail of destruction along the coast might serve as a clue, but even the fastest amongst the other fighters isn't as fast as the beast. Some of them vanish into thin air, some vanish other people, but most have to move very fast.
...It's not just messing with the ocean on the surface. It's messing with the entire giant not-tile, digging through and causing steadily worsening earthquakes. She stops chasing it, lands, turns porous water-filled rock (why does it go on so deep and then melt) into solid-packed stone of the most durable kind she knows. She holds a section of the landmass several tiles' radius around as steady as she can.
She can evacuate a few hundred people (she does try to move people to safety when it's convenient), or she can keep an area the size of dozens or hundreds of tiles from collapsing completely, bringing plural cities with it. She keeps up the fly-after-it-strengthen-and-reverse-dama
And there's so much land, and so much water, and it's soon clear that not even the tidal waves are limited to where the beast is, but rather just periodically wreck more of the landmass. Her help is greatly appreciated, however, and the damage would be clearly far worse if she weren't around.
She's getting tired. Manipulating whole islands is not trivial even for a Fate of the Mountain. She switches to evacuation, which is more attention-intensive than power-intensive. She doesn't ask people whether they'd like to be evacuated, she just grabs them dozens at a time and carries them to hastily made plateaus.
The beast suddenly zaps farther inland and north, not paying much mind to being stealthy for now, and is soon out of view again. The water doesn't seem to have noticed its master has left, though.
There's really not much else she can do. Alternate between evacuating people and hitting the monster, then reverse or limit some of its damage to the island after five minutes of, not rest, but somewhat lower activity.
When it's halfway up, she grows a flash-fast spar of stone around all its limbs except the tail. And then starts emptying the top of that particular plateau, because it's going to get free.
She punches it in the face with a diamond spike. This predictably does little to save the rest of the people there.
And Mountain is just about tapped out now. She flies somewhere (relatively) safe, one of the locations she'd been evacuating to with all the red tents, and pretty much collapses, still in her armor.
When she wakes up, perhaps two hours later, she can't detect it. She finds someone not busy being badly injured or helping people who are, makes a stone caricature of the monster and points it in various directions. Where did it go?
She nods and flies that way, fixing a few roads that have visible amounts of stuck traffic but otherwise saving her strength. She follows the path of destruction until she finds the monster or the path ends, meaning it was killed or gave up.
as it heads back the way she's coming. Through the rain-caused darkness she can see quite a lot of destruction there as well, and the creature doesn't stop to greet her. It stops for a second to topple a building, and she'll be able to notice it's visibly injured, but that doesn't seem to be affecting it in the slightest.
She untopples the building. Then starts trying to slow it down again. She's visibly slower and less powerful than when she fought it before, but she's still damn well going to try. Who's doing the most damage to it, so she can prioritize protecting them?
There are apparently a handful of people who seem to be capable of dishing out the hurt: one human male in a green bodysuit with metal armor who's throwing lances made of energy at it, one in a blue-and-white bodysuit who can shoot lasers with various effects, and one female who can seriously pack a punch. The one in the bodysuit teleports himself and the other two whenever the monster gets too far out of range, and they don't seem to be needing much protecting.