Path of the Sentinel:

These Barbarians are the protectors of their tribes, the most barbaric defenders in settlements, or the tanks of those who they see as friends. Sentinel Barbarians are those who don't need a deity’s power, ancestors’ spirits, or any other supernatural powers to gain their resilience to damage and stare threats down. They just need their natural resistances and strength to gain their tanky body.

This subclass is all about tanking, protecting others, and keeping the threat on them and not others around them.

Great Weapon Defence:

At the beginning of 3rd level. While you are wielding a Greatsword, Greatclub, Greataxe, or a Warhammer you can reduce the damage taken with the weapon damage as a reaction, this will last until the start of your next turn. You cannot perform the reaction while wielding a Shield.

Additionally, you gain proficiency in Heavy Armor and while wearing said armor you still get the benefits of rage.

Power-House:

Starting at 6th level, you gain resistance to a damage type of your choice. You can choose another damage type at 12th, 15th, 17th, and 20th levels.

Come and Get It:

At the start of 10th level, while raging and as a bonus action, you can force all nearby hostile creatures within a 15 feet radius to roll a Wisdom Saving throw DC (8 + proficiency bonus + Strength Modifier). If they fail, they cannot move 15 feet away from you and have disadvantage over any other creatures excluding you until the start of your next turn. You can perform this equal to your proficiency bonus and you regain all expended points when you finish a long rest.

The range of the radius is increased to 25 feet at 15th level.

Wrath of the Protector:

At 14th level, you gain an extra attack. While raging and at the start of each of your turns after your first turn of rage, you gain temporary hit points equal to half of your Barbarian Level rounded up.

Great Weapon Defence

At the beginning of 3rd level. While you are wielding a Greatsword, Greatclub, Greataxe, or a Warhammer you can reduce the damage taken with the weapon damage as a reaction by rolling the weapons damage dice once only, this will last until the start of your next turn. You cannot perform the reaction while wielding a Shield.

Additionally, you gain proficiency in Heavy Armor and wearing Heavy Armor will allow you to gain the benefits of Rage.

Power-House

Starting at 6th level, you gain resistance to a damage type of your choice. You can choose another damage type at 12th, 15th, 17th, and 20th levels. 

Acid

You resist acid damage.

Cold

You gain resistance to cold damage.

Fire

You gain resistance to fire damage.

Force

You gain resistance to force damage.

Lightning

You gain resistance to lightning damage.

Necrotic

You gain resistance to necrotic damage.

Poison

You gain resistance to poison damage.

Psychic

You gain resistance to psychic damage.

Radiant

You gain resistance to radiant damage.

Thunder

You gain resistance to thunder damage.

Come and Get it

At the start of 10th level, while raging and as a bonus action, you can force all nearby hostile creatures within a 15 feet radius to roll a Wisdom Saving throw DC (8 + proficiency bonus + Strength Modifier). If they fail, they cannot move 15 feet away from you and have disadvantage over any other creatures excluding you until the start of your next turn. You can perform this equal to your proficiency bonus and you regain all expended points when you finish a long rest.

The range of the radius is increased to 25 feet at 15th level.

Wrath of the Protector

At 14th level, you gain an extra attack. While raging and at the start of each of your turns after your first turn of rage, you gain temporary hit points equal to half of your Barbarian Level rounded up.