Let's come up with an amphibian race!

Now we need to come up with a history and activities for this race, and that's it, we send it to Nival.

Well... you already suggested an excerpt from the chronicle. Now we need a history)). Let's think.

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Regarding the Something. I think that the hole (whirlpool) should suck in some percentage of the stack's general health, but not less than a certain minimum (say, 70 hp).

Added after 5 minutes

Sea rift-sea abyss

For the Something, I think it's better not to specify which abyss it belongs to. I believe Alexey's option is better: Abyss and Dark Abyss.