Sword and Sorcery (5e)
By sacrificing Vitality equal to the level of the spell attempted the Blood Caster may circumvent the usual Material and spell slot components associated with casting a spell. All penalties associated with this loss of Vitality are accrued as a result of this expenditure. This ability may be used a number of times equal to the casters constitution modifier (minimum one) per long rest as long as the Blood caster has no levels of exhaustion. If the caster attempts to use a Blood casting while they have a level of exhaustion they suffer from system shock and must make a DC 15 Constitution save with their current Vitality as their constitution score or suffer from a lingering injury
If a Blood Caster loses concentration on a Spell Fomented by blood they gain a level of exhaustion.