I see, but that brings me to a thought. An intelligence gathering mission, which could not be done by a human, like possessing a fish and swimming down the see to recover some intel from a wrecked ship, or just swimming past the guards and stuff, you know. I imagine you can possess for only a limited amout of time, but if the mission is centered around completing it as a possessed creature, you might need to find a secure place and put yourself into a deep meditation, which would allow you to control the creature through a lengthy amount of time.
You literally possess others. When you stop you pour out of one of their orifices.
Instead, we possess a guard, taking advantage of Dishonored’s curious form of possession, in which your body physically enters your host, and can pour out of it, through whatever orifice, in its new location. This will traumatise the host – the guard doubles up, vomiting, as we leave him.
http://www.pcgamer.com/2011/08/08/dishonored-preview/
Which means if the protagonist can possess fish, when he stops he'll be disgorged into the water the fish swims in. Ergo, the protagonist should be able to swim... or it'd be suicide.
