Vigor Vampirism
To a Vigor Vampire, you are graced with not only the ability to gain life itself from your opponents, but to take the very essence of who they are and make it your own. This skill is seen as evil by many, but to those who use it, it can be intoxicating.
Starting at 3rd level when you choose this concentration, whenever you strike a being with blood (as ruled by the DM) with your blood weapons, you regain 2 hp up to your maximum. This increases to 4hp at level 6. If you score a critical hit against a living organism, you may regain half of the damage dealt (rounded up) as health.
Beginning at 6th level you gain the ability to drain energy from those recently deceased. If a being with blood (as ruled by the DM) has died within the last minute, you may spend 10 minutes draining it's life force. You gain Hit Points up to one-fourth (rounded up) the creature's maximum Hit Points.
At 11th level, you gain the ability to drain from a short distance. You can rip blood from an enemy with blood (as ruled by the DM) and siphon it into your own pool. At a range of 20 or lower, make a ranged spell attack with Constitution as your modifier. On a successful hit, the enemy takes 2d10 necrotic damage. This damage becomes 3d10 at level 15 and 4d10 at level 18.
At 14th level, you gain the ability to drain the very abilities of your opponents. If you spend an hour of concentration transfusing blood between yourself and another creature, you can take 1 point from a physical ability score of theirs (Strength, Constitution, Dexterity) and add it to your own. You can do this for only 10 minutes as well, as a result you can gain 2 points in any one score, but the ability fades away in 1d4 hours. In either capacity, this can only be done once per day.