Homebrew Astral Merfolk (Aetherial Expanse) Species Details

The merfolk of the Aetherial Expanse make their home in the Constellation Isles, where they’re locked in eternal enmity with their age-old foes, the astral merrow. The merfolk of the Constellation Isles tell tales of tumbling into this world of eternal, starlit twilight long ago. And though many of their kind died—or worse, mutated into merrow—over time, they became at home in the aether.

The magic of the expanse has made their skin bright with shining colors, and given them the uncommon ability to shapechange their long tailfins into legs with webbed feet, which allow them to walk comfortably on land. Though astral merfolk are most at home in the aether, and try to steer clear of the greed of land dwellers, the allure of those who walk on land and sail on wooden ships often proves too great to resist.

The astral merfolk have built a society in the Constellation Isles on the isle of Larmeath and try to live a peaceful life despite the constant predation of their fallen kin, the merrow. Nevertheless, some merfolk dream of more than a placid life in Larmeath disrupted by vicious merrow attacks. Longing for more from their charmed life, these merfolk seek out pirate ships, and the glory and danger those ships chase.

Astral Merfolk (Aetherial Expanse) Traits

As an Astral Merfolk, you have the following racial traits.

Ability Score Increases

When determining your character’s ability scores, your Dexterity score increases by 1, and two other ability scores of your choice also increase by 1.

Languages

Your character can speak, read, and write Common and speak and understand Aetherian, the language of aetherbeasts.

Creature Type

You are a Humanoid.

Size

You are Medium.

Speeds

Your walking speed is 0 feet and you have a swimming speed of 30 feet.

As an action, you can transform your tailfin into a pair of legs. While transformed, you lose your swimming speed and increase your walking speed to 30 feet.

Aetheric Adaptation

You can breathe air, aether, and water and are immune to the effects of aether poisoning.

Slipstream

When you take the Dash action while swimming, you gain extra movement equal to twice your swimming speed. Until the end of your turn, you don’t provoke opportunity attacks while swimming. 
Once you use this feature, you can’t use it again until you complete a short or long rest.

Aetherbeast Affinity

You learn the animal friendship spell, and when you reach 3rd level, you also learn the animal messenger spell. You can cast these spells without expending a spell slot a number of times equal to your proficiency bonus (both spells count toward the same limit), and you regain all expended uses when you finish a long rest. When cast this way, the spell can only target Aetherbeasts. 

You can also cast these spells using spell slots you have of the appropriate level. Charisma is your spellcasting ability for these spells. Casting these spells with a spell slot removes the Aetherbeast targeting restriction.