It was suggested to me that I design an aquatic ranger by Ryan Boelter (@lordneptune), and I did just that. Remember kids, when you design fun aquatic options, you still want to make those designs fun on land too! I am pretty confident that the Thalassic Predator accomplishes that.
Ranger Archetype: Thalassic Predator
The sea is full of more monsters than most places in the world and in order to hunt them, thalassic predators are rangers learn to hunt by studying the most fearsome predators of the depths. Even though they specialize in marine environments, this does not mean they are fish out of water when drawn into battle on land. Their cunning and deadly methods of combat are more than relevant out of the sea and bring the terror that the depths hide to the surface.
Thalassic Predator Magic
Starting at 3rd level, you learn an additional spell when you reach certain levels in this class, as shown in the Thalassic Predator Spells table. The spell counts as a ranger spell for you, but it doesn’t count against the number of ranger spells you know.
Thalassic Predator Spells
|3rd||create or destroy water|
|17th||rary’s telepathic bond|
Underwater you are just as swift as any other undersea predator. At 3rd level, you gain a swim speed equal to your walking speed. If you already have a swim speed from your race, your swim speed increases by 15 feet. Also, while you are underwater, opportunity attacks against you have disadvantage and you can hold your breath for a number of rounds equal to twice your Constitution score if you otherwise can’t breathe underwater.
Beginning at 3rd level, the speed with which you attack makes you a deadly combatant on land or sea. When you take the attack Action on your turn, your speed increases by 10 feet until the end of turn. Once per turn if you hit a creature with a weapon attack after moving at least 10 feet, you can deal an extra 1d8 damage of the weapon’s type. When you reach 11th level in this class, the extra damage increases to 2d8.
At 7th level, you learn to utilize your foes’ own frantic attacks to make way for your escape. Whenever a creature misses you with an opportunity attack, you have advantage on Dexterity (Stealth) checks to hide from that creature until the end of your turn.
Additionally, while you’re hidden If a creature would roll a successful Wisdom (Perception) check to find you while you are hidden. You can use your reaction to count the creature’s roll as a failure and move up to half of your speed. You can use this reaction a number of times equal to your Wisdom modifier (minimum of once). You regain all expended uses of it when you finish a long rest.
You hone in on your prey and tear into it into with a vicious tenacity. Beginning at 11th level, when you hit a creature with twice with a melee weapon attack on your turn, you can make one additional attack against that same creature that turn. Your additional attack scores a critical hit on a roll of 19 or 20.
Starting at 15th, your attacks hamper your quarry in such a way that retreat is more dangerous than fighting you to survive. The first time you hit a creature during your turn with a melee weapon attack, that creature’s speed is reduced by half and it can’t take the Disengage action until the start of your next turn.
Unearthed Arcana Revised Ranger
If you are using the Unearthed Arcana Ranger, you gain Extra Attack at 5th level as a Thalassic Predator.
Art: Josu Hernaiz, Wizards of the Coast Thrasios, Triton Hero