The Path of the Misty Serpent has a ranger take power from nature, and turning it forth into shadows and mist to hide and conceal themselves from the eyes of the world around, stepping away into shadows. Rangers that follow this path often find themselves infatuated and or 'haunted' with the iconography and thought of Ouroboros. This connection to Ouroboros eventually leads one to see between the planes, through the mist per se, being able to slip between planes and worlds. 

Misty Serpent Magic

Starting at 3rd level, you learn an additional spell when you reach certain levels in this class, as shown in the Horizon Walker Spells table. The spell counts as a ranger spell for you, but it doesn’t count against the number of ranger spells you know.

Horizon Walker Spells

Misty Scout

Beginning at 3rd level, you can summon mists at any time as a bonus action. You gain the ability to emit a fog cloud with a 20ft radius, with the target being self.

You and any allies 5 feat away from you can see through the mist.

You can use this ability a number of times equal to your proficiency bonus per short rest.

Fangs of the misty serpent

At 3rd level, you learn to draw on the will of Ouroboros to augment your attacks.

As a bonus action, choose one creature you can see within 30 feet of you. The next time you hit that creature on this turn with a weapon attack, all damage dealt by the attack becomes Necrotic or Poison damage, and the creature takes an extra 1d8 Necrotic or Poison damage from the attack. When you reach 11th level in this class, the extra damage increases to 2d8.

The weapon used to make the attack, the ammunition, or weapon appears to have a grey, misty spectral serpent wrapped around.

Step through Mist

At 7th level, you learn to step through the Ethereal Plane. As a bonus action, you can cast the etherealness spell with this feature, without expending a spell slot, but the spell ends at the end of the current turn.

When you're in the Ethereal Plane, your companions are able to see a faint grey mist where your footsteps follow and around anything you interact with.

Once you use this feature, you can’t use it again until you finish a short or long rest.

Serpent strike

At 11th level, you gain the ability to pass between the planes in the blink of an eye. When you take the Attack action, you can teleport up to 10 feet before each attack to an unoccupied space you can see.

When you pass between planes you leave behind a faint grey mist in the direction you teleport. The user decides if the mist is visible or not.

If you attack at least two different creatures with the action, you can make one additional attack with it against a third creature.

Veil of the Serpent

At 15th level, your ability to control the mist that flows around you in battle. When you take damage from an attack, you can use your reaction to give yourself resistance to all of that attack’s damage on this turn. as this happens, the area you are hit or that is damaged, has Serpents mist flow out and slow or dampen the attack before it reaches you.