Invulnerability is a Primary Power Set for Tankers and a Secondary Power Set for Brutes, and Scrappers.
You have incredible resistance to most damage and other debilitating conditions.
At 1st level, you have resistance to bludgeoning, piercing, and slashing damage. In addition, no attack roll against you can have advantage as long as you have more than one half of your maximum hit points.
You gain access to Resist Elements at 2nd level if you're a Tanker and at 4th level if you're a Brute or a Scrapper, Resist Energies at 4th level if you are a Tanker and at 8th level if you're a Brute or a Scrapper, and Tough Hide at 10th level if you are a Tanker and at 14th level if you are a Brute or a Scrapper.
At 1st level, you can shore up your body's physical toughness. You can activate this feature without costing an Action but you must do so on your turn. It will remain active until you deactivate it on your turn, or become unconscious or incapacitated. At the beginning of each of your turns while your Temp Invulnerability is up, you can choose to be immune to bludgeoning, piercing, or slashing damage. This immunity lasts until the beginning of your next turn, and you cannot choose the same damage type twice in a row. You must set aside one Endurance Die to keep this feature active.
You can use Unyielding at 3rd level if you are a Tanker and at 6th level if you are a Brute or a Scrapper, and you can use Invincibility at 7th level if you are a Tanker and at 11th level if you are a Brute or a Scrapper.
At 1st level, you can use your Action to grant yourself 2d4 temporary hit points. At 5th level this becomes 3d4, at 9th level it becomes 4d4, at 13th level it becomes 5d4, and at 17th level it becomes 6d4. If you use this feature while you already possess temporary hit points, the new temporary hit points replace the existing ones.
At 12th level if you are a Tanker and at 15th level if you're a Brute or a Scrapper, you can use your Action to supercharge your defenses. You become immune to a number of damage types excepting psychic equal to your Proficiency Bonus (your choice). Also, you double the value of any Endurance Die roll result. These benefits persist until the end of your turn a number of rounds equal to your Proficiency Bonus after activating this feature. On the turn that this feature ends, you immediately lose one half of your maximum Endurance Dice. Also, when this feature ends your Temp Invulnerability becomes suppressed, you become vulnerable to the damage types you were immune to, and are unable to roll any Endurance Dice until the beginning of your following turn.