I am theory-crafting a character that takes very little damage. I want to use the Heavy Armor Master feat to help with damage reduction from non-magical attacks, as well as the Battlemaster maneuver parry, and the Goliath feature stone's endurance. How can I gain resistance to piercing, bludgeoning, and slashing while also using the Heavy Armor Master feat? I am most interested in answers that don't depend on external sources, such as other characters and magic items, but I'd like to hear answers including those as well. Multi-classing is an option.
I'm going to assume that you want to remain functional, so no being turned into stone or Feign Death.
Ways to gain resistance to bludgeoning, piercing, and slashing damage while also wearing Heavy Armor:
- War Cleric's Avatar of Battle ability
- Oath of the Crown Paladin's Exalted Champion ability (Sword Coast Adventurer's Guide)
- Blade Ward cantrip
- Investiture of Stone spell (Elemental Evil Player's Companion)
- Stoneskin spell
- Armor of Invulnerability
- Boon of Resilience
- As Zso points out, the Oathbreaker Paladin's Supernatural Resistance feature, from the DMG
A 19th-level Goliath Eldritch Knight can independently achieve your requirements.
- Heavy Armor Master
- Martial Adept (for Parry)
At 19th-level, an Eldritch Knight can cast a 4th-level spell, which, in your case, should be Stoneskin.
- Independent of other characters
- No multi-classing
- Still functional and viable
- No Magic Items needed
- Can only cast Stoneskin once per long rest (this can be mitigated by spell-storing items like the Ring of Spell-storing)
- Can only Parry once per short rest
- High level required to achieve this (EKs get 4th level spells at 19th-level)
It is high level but you can use Wish. One for each type you want resistance.
You grant up to ten creatures that you can see resistance to a damage type you choose.
The crux is that each time you cast it for this there is a 1 in 3 chance the caster can't use wish again, assuming mortal caster and not from something like a Genie.
The new unearthed arcana Samurai fighter archetype can gain resistance to bludgeoning, piercing, and slashing as a bonus action on their turn until the end of their next turn, three times per short rest, at level 3.
You would have to take the Martial Adept feat in order to get a superiority die to use for parry, but the emphasis on willpower, the ease of access to heavy armor mastery at level 4 might be appealing.