Crimson Blade

You form a long, thin, blade of fiercely hot blood that you can wield with one hand. This magic sword lasts until the spell ends or is dispelled. It counts as a martial weapon with which you are proficient. You take 1 point of damage and it deals 1d10 fire damage on a hit and has the reach, and finesse properties. In addition, you may sacrifice blood to increase the damage of each strike, this sacrifice is limited based off the level of which the spell is cast.

The amount of hit points you sacrifice is equal to the amount of d10s in each strike. At level 3, you may sacrifice up to 3 hit points at one time per attack.

When you kill a creature with this blade, you gain hit points equal to 1/4th of their hit point maximum. Any hit points you would receive over your hit point maximum become temporary hit points that last for the duration of the spell.

At Higher Levels: You increase the hit point sacrifice cap to 4 hit points at 4th level and 5 hit points at 5th level, all the way to 9th level.