You take… 91 points of fire damage! Yowch, that’s gonna leave a mark! Good thing that tiefling has fire resistance or the dragon’s breath would have cut her down pretty quickly. Now you can see resistance can be very important, let’s take a deeper look:
How Resistance Works
Clear and simple: when you take damage, you reduce your HP by the amount of damage taken. Resistance reduces damage taken by half, but only for the specific damage type(s) you are resistant to. If you take an odd number of damage, you round the end result down, e.g. in our example, 91 fire damage is halved to 45.5, you’d then round down to 45 damage total instead. To go along with resistance, there’s also immunity, and vulnerability: Immunity negates damage entirely, and vulnerability doubles it. You cannot benefit from resistance or suffer from vulnerability twice on the same damage. So our tiefling would not have gained any additional benefit from casting Absorb Elements.
You can benefit from resistance alongside other forms of damage reduction. For example, the Rogue’s Uncanny Dodge ability would stack with resistance so you would take a quarter of the triggering damage instead of only half. Likewise, an ability like the goliath’s Stone’s Endurance would stack with resistance, reducing the damage before halving it. This is because resistance is always resolved last (PHB, p. 197).
Where You Can Get Resistance
Now, resistance is nice, but it means nothing if you can’t get it. Fear not, however, as I’ve got just the thing you need: the where and how of getting it.
To start, races. Some races, such as dwarves (poison), tiefling (fire), aasimar (radiant and necrotic), and dragonborn (dependent on their ancestry), are born with resistance to specific damage types, listed in their racial traits.
There’s also a variety of spells that grant resistance, including: Protection from Poison (poison), Absorb Elements (varies), Stoneskin (non-magical Bludgeoning, piercing, and slashing), and Protection from Energy (varies).These are just examples, so you’ll want to check those Abjuration spells. Plus, some spells like Mind Blank, actually grant Immunity to certain types of damage, though at a high price.
Then, of course, there’s magic items that grant resistance. Examples include: Armor of Resistance (varies), Brooch of Shielding (force), Potion of resistance (varies), Ring of Warmth (cold), Absorbing Tattoo (varies), and to top it all off, there’s even items like Armor of Invulnerability which grants immunity to non-magical damage as well!
Keep in mind, the above are just samples of resistances and ways to go about getting them. Feel free to let your inner munchkin out now and then as you purposely create your own sentinel of health. Resistance is incredibly valuable and can really knock your survivability out of the park if used correctly. Find something cool you can use, or work with your DM to create your own resistance homebrew, and just see where everything takes you. And most importantly, have fun!