Mark of the Sanguine

Whether though teaching or discovery, you have found that your blood holds magical power.  You might have chanced upon a reclusive use of this forbidden magic, or within an ancient tome with runes scribbled on pages marked in blood; in either case the power that your blood hold has awoken.  By tapping into your life force, you are able to bring your power into reality.  Sorcerers of this origin are not held in high regard as most are shunned or even killed, due to the lack of understanding and fear.  Though the power you weld may be terrible and awe-inspiring, it is without question, undeniable. 

Resilient Blood

Starting at 1st level, 

When you finish a short rest, you can choose to regain hit points equal to your Constitution modifier + half your sorcerer level (minimum 1).  Once you use this feature, you cannot regain it until you finish a long rest.

Hematurgy

Starting at 1st level,

As a bonus action, you can spend up to 5 hit dice and take 1d6 damage per die.  The next sorcerer spell cast doesn't cost a spell slot or components.  You cannot use this feature to cast a higher-level spell than you have spell slots for.  You must finish a long rest to reuse this feature.

Also, you also gain the ability to expend your life force more directly in the pursuit of powerful magic.  As a bonus action, you can spend any amount of hit dice, gaining 1 sorcery point per hit die spent.  You cannot gain more sorcery points than current character level.  You cannot expend more hit dice using this feature that half of your sorcerer level (minimum 1).  You must finish a long rest to reuse this feature.

Bleed Magic

At 6th level,

When you take bludgeoning, slashing or piercing damage or damage from a blood spell, you can spend 2 sorcery points to use your reaction to cast one spell that would be either an action or bonus action to cast.  You cast this spell after you take the damage.

Crimson Power

At 14th level, if you have half of your hit points at the beginning of your turn, you gain a +3 to AC.  If this is active, add your proficiency modifier as bonus damage once per turn.

Sanguine Storm

Starting at 18th level, when you deal damage to a creature and reduce it to 0 hit points, you can spend 2 sorcery points to cause the creature to violently explode.  The target fails 1 death saving throw automatically.  Each creature within a 15-foot sphere centered on the target must make a Constitution saving throw or take 7d6 necrotic damage, half damage if saved.