Understalker

Living beneath the surface isn’t easy, pleasant, or pretty, but if you’ve got the guff for it there are secrets to be gleaned from a hard-lived subterranean life. Whenever there’s a ceiling above your head you are in your element, operating with a paranoid energy that makes you into a truly lethal hunter.

Subterranean Stalker

At 3rd level, you can see normally in darkness, both magical and nonmagical, to a distance of 120 feet. In addition, while inside of a building or underground you gain the following benefits:

• Advantage on hearing-based Perception checks.
• A +3 bonus to your passive Perception.
• Advantage on Wisdom (Survival) checks.

Under Combatant

Starting at 7th level, while you are inside of a building or underground you gain a 1d6 bonus. At the start of each round you choose to add this bonus to your AC against one opponent you can see, a weapon attack roll, or a weapon damage roll.

Under Hunter

Beginning at 11th level, you can spend an action to roll d20 and add your ranger level, analyzing a creature that lives underground. If the result is higher than the Challenge Rating of the target, you know its resistances, immunities, abilities, and attacks. You must be able to see or hear the target. If you use this feature against a creature that does not live underground, you only add your proficiency bonus to the d20 roll.

Master Stalker

At 15th level, your under combatant feature applies to all opponents you can see as well as all weapon attack rolls and all weapon damage rolls you make.