Warpath:
By the time you have chosen this path at 3rd level, you've tapped into a deep well of strength and power. As a Warpath, you gain the following benefits if you aren’t wearing heavy armor:

You gain temporary hit points equal to ten times your Berserker level, adding your Constitution modifier to the total. At 10th level, this increases to fifteen times your Berserker level. Temp HP resets after long rest
While you are not wearing any armor, your Armor Class equals 12 + your Constitution modifier + your Strength modifier. You can use a shield and still gain this benefit.
You have advantage on all Strength checks that involve grappling.

Strength from Pain:
What doesn't kill you makes you stronger. This is the creed of all berserkers and you know it well. Starting at 2nd level, when a creature deals damage to you, you can use that pain to fuel your combat prowess. On your next turn, as part of your attack action, you can deal additional damage on your next successful melee attack equal to half the total damage that creature would have dealt. For example, if an opponent rolls a 12 on their greatsword strike and adds 4 due to their Strength modifier, you can deal 8 additional damage with this feature, regardless of resistances. This damage can only apply to the target that dealt that damage to you.