Dungeoneer

Only fools would think to dive headfirst into an abandoned crypt filled with monsters and deathtraps, but it seems only fools emerge from such crypts laden with as much loot as they can carry. The archetypal dungeon delver is a veteran of such suicidal dungeon delves, and has become intimately familiar with the hazards therein. In the course of their adventures, such a dungeoneer will have adopted countless best practices, along with a litany of unproven superstitions which they believe keeps them alive. Principles from “always be the first one to hit the monster” to “never be the first one to touch a treasure chest” line a dungeoneer’s journal. However, it’s probably better to be paranoid and superstitious than lying at the bottom of a pit trap, incinerated by a fireball, or digested by a mimic.

Level 3: Danger Sense

You have advantage on Dexterity saving throws against effects that you can see, such as traps and spells. To gain this benefit, you can’t be blinded, deafened, or incapacitated.

Level 3: Kick in the Door

You know how to charge through each chamber of a dungeon and come out alive. You have advantage on initiative rolls. Additionally, when you are not surprised and you initiate combat by kicking down a door, diving in from overhead, crashing through a window, or any other suitably reckless tactic (as adjudicated by the GM), you have advantage on attacks against creatures you can see during the first round of combat.

Level 7: Dungeoneer's Intuition

You have a sixth sense for the unique hazards present in a dungeon. You have advantage on ability checks you make to detect shapechangers, traps, and unseen magical effects, and can make a check to detect such hazards even if you would not normally make such a check.

Level 10: Monster Kill

When you hit an Aberration, Fey, Fiend, Monstrosity, Ooze, or Undead with a weapon attack, you can deal an additional die of damage to the target. You can use this feature three times, and you regain all expended uses when you finish a short or long rest.

Level 15: Lethality Prevention

You are a foremost expert in avoiding death. Whenever you would take more than 50 damage in a single turn, but the damage wouldn’t kill you outright, you instead take only 50 damage.

Level 18: Avoidance

to an effect that allows you to make a Strength, Dexterity, or Constitution saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.