Let's come up with an amphibian race!

If we want something more warlike, we can phrase it like this. The flexibility of water and the solidity of earth – that is our essence. A cleansing flood will wash away the enemy, and the earth will swallow him.

Much better. The second line is connected to the first, and we've already come up with the "Flood" spell. So, we need to come up with a combat earth spell as well. For example... hmm... I need to think about it.

Added 2 minutes later
If the earth swallows, then it should be something like "Absorption into the Earth's Depths"... But we need to come up with a more beautiful and concise name.