You have resistance to psychic damage and advantage on saving throws against being frightened. Additionally, you gain the benefits of a Long Rest after 6 hours and can still make Wisdom and Intelligence checks during that time with disadvantage.

You have blindsight of 10 feet and can see through water as easily as you see through air. When you are surrounded by at least 20 feet of water in any direction, your blindsight extends to 20 feet in those directions.

At the being of combat, before each creature rolls initiative, you may choose one creature you can see within 60 feet of you. That creature must succeed in a DC 14 Wisdom saving throw or subtract 2 from their initiative roll. If they succeed, you may choose a second creature to use this on, but you may not choose a 3rd if that one also succeeds. If you use this ability, you gain 2 on your initiative roll.

You may use this feature a number of times equal to your proficiency bonus, regaining all expended uses after a long rest.

You have a legacy from the deepest chasms of the ocean and the farthest reaches of space. You may choose one of the following options:

• Legacy of the Sea. You can breathe in both air and water, and you have resistance to cold damage. You also know the Shape Water cantrip.
• Ancient Legacy. You can cast Protection from Evil and Good once per long rest, but it only protects you against Aberrations, Monstrosities, and Oozes. You also gain proficiency with 1 tool of your choice.

You reach maturity around age 100 and live up to 600 years. However, if a Fathomless spends at least 1 month a year hibernating underwater, they age at half the speed for the next 11 months.

Your unarmed strikes deal 1d4 slashing damage.

Your Wisdom score increases by 2 and you may choose to increase your Constitution or Intellegence score increases by 1.

Your size is medium.

Your base walking speed is 30 feet.

You can speak, read, and write Common and Deep Speech.