Berserker

A tall human swordsman strides through a blood-soaked battlefield, wielding that which was too big to be called a sword, massive, thick, heavy, and far too rough. Indeed, it was a heap of raw iron and of all men who walked that battlefield that day, none could doubt that mans strength or that weapons impracticality as he dyed its black steel crimson.

Despite a commander's best efforts, no magic of the Weave, nor blade made of man could stop the indomitable goliath that broken the will of all men who dared walk before him, as if he was an avatar of war itself, he warped what was the twisted stench of death and strive, into a one-sided conquest through his immeasurable fortitude and strength, for he alone was the Hell walker.
In the darkness of the forest, an enemy scouting party stops, disturbed by the slender figure of a man who blocks their path, his unblinking eyes watching them like a wolf of the night. Granted power through the teachings of Fenrir, his movements are fast and unrelenting, as he cleaves through the unit like the beast himself. In his ravenous bloodlust he found no satisfaction; and with rushing blood he scoured the forest of those who had fled, their wounds carving a path to them through the dense foliage and sealing their inescapable fates.

As if possessed by the Æsir themselves, his iron will remain steadfast against the hellfire that threatened to consume him, shielding the weak and defenseless with his own body as the flames seared his flesh and bone, but it was then when the fires subsided that the man marched towards the servants of hell, hunting them with barbarous cruelty as if he had passed through the divide as none but demon had before.
A Berserker makes his place in any battle, dying a thousand times and walking out alive, surviving wounds and attacks that would kill most only to come back the next day in search of his next fight. Their insatiable desire for battle leads them to become fierce nigh-unkillable soldiers of war, that embody some of the most dangerous beings of the Norse pantheon, primary, Fenrir and the Æsir. All those who face a Berserkers wrath be warned, for their presence and will alone break even the most fearless of men...

Warpath

On your turn, you can enter a warpath as a bonus action. While on a Warpath, you gain the following benefits if you aren’t wearing heavy armor:

You gain temporary hit points equal to five times your Berserker level, adding your Constitution modifier to the total. At 10th level, this increases to ten times your Berserker level.
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.

You can ignore the two-handed weapon property on weapons, allowing you to wield a shield and a two-handed weapons in one hand.

If you are able to cast spells, you can't cast them or concentrate on them while on a warpath. Your warpath lasts for 1 minute. It ends early if you are knocked unconscious or if your turn ends and you haven't attacked a hostile creature since your last turn or taken damage since then, ending this effect early causes a level of exhaustion. You cannot end your Warpath otherwise and once it ends you cannot re-enter a warpath for 1 minute. Once you have entered a warpath the number of times shown for your Berserker level in the Bloodrush/Warpath column of the Berserker table, you must finish a long rest before you can enter a warpath again.

Mocking Bellow

While on a warpath, as an action you can taunt all hostile creatures within a 30-foot cone. All hostile creatures must make a Wisdom saving throw versus your Berserker save DC. On a failed save, they must use their reaction to move their speed towards you and for 1 minute they have disadvantage on attacks against anyone other than you. Any affected creatures can remake their save each time they take damage from you. This effect ends early if warpath ends. Once used you must complete a short or long rest before you can use this feature again. Creatures that are immune to the charmed condition are immune to this feature.

Asgardian Reserve

When your hit points are reduced to 0 while on a warpath you regain 1 hit point and gain half the temporary hit points, rounded down, you would usually get when entering a warpath. Doing this extends the duration of warpath as if you had just entered one. These temporary hit points last until depleted or warpath ends. If you don't have any uses of warpath left when this feature would trigger, it doesn't. You must finish a long rest before you can use this feature again.

Brick by Brick

Whenever you take more than 50 damage you can, instead of taking that damage, take 50 damage as an irreducible amount of typeless damage. You can use this feature a number of times equal to your Constitution modifier. You regain all expanded uses when you complete a long rest.