You can breathe air and water

You are proficient in the following special wwapons:Sai (dagger), Bo-Staff (quartersatff), Nunchaku (clubs), and Katanas (scimitar) thanks to all the training

Your eyes have adapted to the darkness of the undergrounds. You can see in dim light, and in darkness as if it ere dim lights. You can´t discern colo in darkness, only shades of gray

You can attempr to hide even when you are only lightly obscured by foliage, heavy rain, falling snow, mist, and other natural phenomena

You can withdaraw into your shells as an action
Until you emerge, you gain a +4 bonusc AC, and you have advantage on Strength and Constitution saving throws. While in your shell, you are prone, your speed is 0 and can´t increase, you have disadvantage on Dexterity saving throws, you can´t take reactions, and the only action you can take is a bonus action to emerge from your shell.