[@azoicsiren ]
It was the matter of which you took control of someone else's character in an unapologetic manner both beginning and afterward that essentially was pointing toward strong plot point with no second thought about it that disturbed me for the most part. There was no mention of the witch being at the scene, and given the context it appeared to be a mystery about the witch possibly being among their own ranks or somewhere else setting up the traps. I would understand perhaps another witch or monster you created showing up (but this was not the route you aimed for, nor did you ask permission or mention this to anyone else beforehand) , but taking it over and then saying the witch 'wilted' as a character smiled down and swam away implies decaying away and dying, not survival though I will admit this is a misinterpretation on my end. 

I'm not saying you have to plan for everything but be considerate of others and wary of your own characters abilities and weaknesses. You could create new demons, new traps, new troubles, new plot points, new events and new characters to get involved if you want to surprise someone. You can pull something out of your backstory, maybe your character has a strange realization that they need to share, perhaps they found something interesting or something in their backstory comes up for the rest of the characters to experience, you can do a lot of stuff it doesn't need to be planned point by point. Heck, ya had a kappa or creature of your own trying to lure ya into the water at the beginning (which worked) so you could've kept going with that. 

As for powers, personally it seems incredibly overpowered that you could turn an entire pond to [b]pure acid[/b] within a singular post (not to mention assume someone survived that after mentioning them withering). Also, literally everything is made of chemicals and chemical compounds, but that wasn't my call that was Hitman's, on top of your other powers of hypnosis, injecting people with venom and being able to control toxic or poisonous substances along with turning non-harmful elements into lethal substances which can then be manipulated (so really you can manipulate the nature of just about anything that isn't magically protected and make it healing or lethal) which is now argued to be chemical compounds , which again is literally everything. Unless you edited that power (seeing as it was edited seven days ago). There is also no mention of her being immune to her own power and no mention of especially being immune to pure acid for that matter  or even being able to affect things on such a scale on her character sheet. Immunity is less the point that I'm upset about and more the point that she was capable of doing this on a large scale in an element that not only she was weak to, was she surprised attacked in, didn't have time to prepare, and was running out of oxygen. 

One could argue she only turned the water around the witch into acid (though depending on how much it could spread, but that wouldn't be an issue), which would be an effective argument rather than downright immunity to an entire pond full of acid.