Path of the Masochist

The woman stands unmoving in the rain, her elven slavers screaming at her, their whips cracking against her skin. She laughs, like a crack of thunder. Her bulgin muscles, thick and corded from years of breaking rocks in the quarries, tense and her chains snap. She laughs as they cut and stab at her. She laughs as she tears them, limb from limb. They can't break her. She loves the pain. She laughs, and laughs, and laughs.

The leonin warrior swing his greataxe at the orc berzerker in front him. The orc, defying the leonins expectations doesn't dodge, he takes the full brunt of the heavy blade into his shoulder. He screams with rage into the leonins face, seeming to grow. He brings his twin axes down in a flurry of blows. The leonin can see the exposed muscles in the orcs shoulder tearing as he attacks with relentless ferocity, driving his hand axes into his chest, neck, arm, should and finally, head. The last thing the leonin warrior sees is the orcs face, eyes glowing with battle lust, his blood smeared face grinning wide.

 The loxodon stomps into battle, his trumpetting cries loud. He watches as two fighters charge away from him at the tiny gnome friends who took him in, a wizard preparing to fire off a spell that would surely turn their home to cinders. "You pissweak rabble! You cower away from me! Do you have no honour! No pride! I am the greatest warrior here, it is at your folly you would turn your back to me!" The warriors turned, the wizard faltered, looking at the towering elephantine figure. The loxodon smiled as one of the warriors loosed a heavy crossbow bolt that pierced into his gut, the shock like the loving kiss of his fathers fists. "Good, now we can have some fun!" and he charged his maul gripped tightly in his massive hands.

Those who take this path often have lived hard, torturous lives. To them pain is many things, a reminder of what it means to be alive, perhaps it is like the gentle caress of an old lover, or maybe it gives them gratification and pleasure so profound nothing can match. Many who take this path are truly wild in their ferocity, for there is nothing you can do when the creature you're trying to kill, loves to live on the edge of death and feeds on every strike, every spell, every bit of the damge you inflict. 

Strengthened by Pain

Whenever you take damage you may immediately enter your rage as a reaction. Once per round, while raging, the first time you take damage you gain temporary hit points equal to half your barbarian level (rounded up) plus your constitution modifier.

Bloodied and Smiling

Whenever you are below half of your total hit points, and raging, you are Bloodied and Smiling. While Bloodied and Smiling you can make a number of additional attacks as a bonus action, equal to the number of attacks you make with the attack action (up to a maximum of two attacks). If you have the two-weapon fighting bonus action, you may make an additional attack. Additionally, if at the end of your turn you are below 10 hit points, but not at 0 hit points or less, you regain hit points equal to your constitution modifier. 

Reckless Abandon

From 6th level, you learn to fight with such ferocity you can tear at your own muscles to cause even greater harm to your enemies. Whenever you attack recklessly, you take damage equal to a roll of your Reckless Abandon dice (1d6 at level 6), the damage type matches your weapon damage. On a successful hit you may roll your Reckless Abandon die and add it to your weapon damage. If you are Bloodied and Smiling you also critically strike on a 19+ while fighting with reckless abandon. 

The dice increases as you reach level 10 (1d8), 14 (1d10), and 18 (1d12).

Vicious Taunt

Starting at 10th level, you taunt and jibe your enemies to ensure that your receive the pain they would inflict, not another. Whenever a creature within 30ft of you makes an attack or casts a single target spell that deals damage against a target other than you, you may use your reaction to become the target of that attack instead. The creature must make a Wisdom saving throw (DC equal to 8 + your proficiency bonus + your Charisma modifier). On a fail, that attack or spell must target you instead. If you are outside the range of the attack or spell or cannot be targeted by it for any other reason, the creature instead has disadvantage on all attacks against targets other than you until they attack you or the end of their next turn.

Focus on the Pain

From level 14, your love of pain has made your tolerance for damage, and endurance in combat, unrivaled. If you are Strengthened by Pain, when you take damage only reduce your Temporary Hit points, the damage does not carry over to your normal hit points.

While you are Bloodied and Smiling, if you would take damage that you do not already reduce by any means, make a constitution saving throw. The DC equals 10 or half the damage you would take, whichever number is higher. On a success, you reduce the damage you would take by half.