I find the setting of Warhammer fascinating, as a writer and a roleplayer. It seems like everyone and everything in the Old World sucks, and that poses an existential challenge to any adventurer who aspires to moral virtue. It is easy to be brave and heroic in a world that encourages hope and valor. Bravery and heroism become more difficult, and therefore more impressive, in a world that passively discourages them, or indeed that promises to kill you for your efforts. I think Dwarfs, easily the race most concerned with honor and glory, have answered this problem of heroism with the Slayers. The Slayers are a distilled incarnation of the understanding that life is unpleasant, and the best one can hope for is to die in a way worth remembering.
I think this attitude could make a fine addition to Dungeons and Dragons, whose settings tend toward a tacit approval of good-natured adventure. To this end, I have attempted to recreate the concept of the Slayer as a 5e Barbarian subclass. I hope for honest and constructive criticism, with attention given to a) how it conveys what a Slayer is in D&D mechanics; b) how balanced it seems, compared to other mechanics of similar power level; and c) whether it looks like fun.
Thanks in advance!

Spoiler: Slayer Subclass
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Path of the Slayer
Dwarves who have been disgraced, crossed in love, or otherwise humiliated abandon traditional society and seek the sweet release of death. They hunt the most dangerous of monsters in the hopes of finding a glorious end.

Restriction: Dwarves Only
Only dwarves can follow the Path of the Slayer. The cult of the Slayers is esoteric and strange, the oaths they take incomprehensible to any without the dwarves' obsession with honor.
Your DM can lift this restriction to better suit the campaign. The restriction exists for the Old World of Warhammer. It might not apply to your DM's setting or your DM's version of the Old World.

Lost Proficiencies
Starting when you choose this path at 3rd level, you lose proficiency with medium armor and shields.

Fighting Style
When you choose this path at 3rd level, you adopt a particular style of fighting as your specialty. Choose one of the following options. You can't take a Fighting Style option more than once, even if you later get to choose again.
Great Weapon Fighting. When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. The weapon must have the two-handed or versatile property for you to gain this benefit.
Two-Weapon Fighting. When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.

Slayer's Quarry
You have sworn to destroy an enemy of your race...or die trying.
At 3rd level, you choose a type of creature: aberrations, beasts, celestials, constructs, dragons, elementals, fey, fiends, giants, monstrosities, oozes, plants, or undead. Alternatively, you can select two races of humanoid (such as gnolls and orcs) as your quarry.
You have advantage on Wisdom (Survival) checks to track your Slayer's Quarry, as well as on Intelligence checks to recall information about them.
You choose one additional type of quarry at 10th and 14th level. As you gain levels, your choices should push you toward ever greater opponents—adversaries who may grant you the end you seek, or whose own defeat might be worthy of a song.

Stout-hearted
The quest for glorious death is all that sustains you now, and nothing will stand in the way of your destiny.
Starting at 6th level, you have advantage on saving throws against being charmed, frightened, or possessed, and you cannot be charmed, frightened, or possessed by your Slayer's Quarry.

Grudgelord
When you meet a foe you have vowed to kill, only one of you will walk away alive.
Starting at 10th level, while you're raging, hostile creatures within 30 ft of you have disadvantage on attack rolls against creatures other than you.
While you are within 30 ft of your Slayer's Quarry, you have disadvantage on attack rolls against creatures other than your quarry, and you must succeed on a Wisdom saving throw in order to move more than 30 ft away from your quarry. While you're raging, any of your Slayer's Quarry must make the same save to move more than 30 ft away from you. The DC for this saving throw is equal to 8 + your proficiency bonus + your Constitution modifier.

Mighty Blow
You have become an avatar of doom, and those foolish enough to stray into your path do not often live long enough to regret their mistake.
Starting at 14th level, any melee attack roll you make while raging is a critical hit on a roll of 19 or 20, and your Rage Damage bonus is doubled against your Slayer's Quarry.