Nautilid

The fishlike nautilids are now fewer than they ever have been. At its height, the nautilid race was a force to be feared, with a fleet that fought alongside the elves in the Crusades and an indomitable homeworld, named Poseidon for its endless oceans. Alas, this was never to last. When the cruel fires of their home star consumed Poseidon, the nautilid race was left adrift in their ships, searching for another world that could support them.
Poseidon was a world of unique composition—a mixture of rare elements and gases was dissolved in its deep oceans. This liquid, known as the Poseidon Solution, is central to the nautilids’ biology. Though the nautilid possess great intelligence and are swift underwater, the Solution also allowed them to grow large, for minerals in the Solution facilitate extremely efficient gas transfer into their gills. Nautilids are technically amphibious, possessing both a set of lungs and gills, but venturing too long without the Solution makes respiration difficult. Thus, nautilids ships and aqua suits are filled with Poseidon Solution.

Race Against Extinction

Ultimately, the blessings of the Poseidon Solution have become a curse. Long they have searched, but the nautilids have never found an oceanic planet with similar enough waters to the Solution to start anew, nor can the properties of Poseidon simply be terraformed into a new planet. Nautilid populations are in steady decline, and have been for generations, for only aboard ships with ample Solution can nautilid infants be born.
From their large and water-filled Whorl ships, the nautilids have systematically combed the galaxy for planets that have the potential to become New Poseidon. Every lead and every clue are analyzed, without exception. In pursuit of this goal, nautilid scientists have pushed the boundaries of exploration and colonization, so far, to no avail. Finding the right planet is like picking a single drop from a sea of stars, if that drop even exists.
It is no secret what is on the line: the nautilids are in an agonizingly slow race against extinction; right now, unfortunately, they’re losing.

Theme

Nautilid Traits

Your great, amphibious body and your constantly-worn aqua suit give you the following racial traits:
Ability Score Increase. Your Strength score increases by 2, and your Intelligence score increases by 1.
Age. Nautilids reach maturity by 20 years of age, and individuals have been recorded to live as long as 150 years.
Alignment. Stoic and contemplative, nautilids tend to be lawful.
Size. Lumbering and stout, nautilids stand between 6 and 8 feet tall, seeming even larger in their cumbersome aqua suits. Your size is Medium.
Speed. Your base walking speed is 30 feet, and you have a swimming speed of 30 feet.
Amphibious. You can breathe water as well as air, though breathing air is uncomfortable for you without assistance.
Powerful Build. You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift.
Deductive. You have proficiency in the Investigation skill.
Aqua Suit. Except when you are aboard a whorl ship, you wear a bulky aqua suit, which is filled with Poseidon Solution, in order to breathe comfortably. The suit covers your whole body, including a large domed helmet with circular windows that allow you to see without hindrance. Without the suit, you can breathe air or water, but doing so delivers air inefficiently to your lungs, and you feel much the same as a human does in very thin air. You can don or doff the helmet on your turn as part of your action, and you can don or doff the entire suit in 1 minute. If damaged directly but not completely destroyed, the suit rapidly mends itself, leaking only a very small amount of water.
    While wearing the suit, your AC equals 13 + your Dexterity modifier. Other armor can be fitted to attach around the aqua suit at no cost. While no other armor is fitted to it, you count as being unarmored for the purposes of features such as Unarmored Defense. Additionally, while wearing the suit, you have resistance to fire damage. The suit counts as a life suit and is also equipped with an embedded universal translator magic item, which you can use at will.
Languages. You can speak, read, and write Common and Aquan.