A D&D 5e sorcerer takes the invocation of Fiendish Vigor.
Let's say that the sorcerer gains 8 CV of Diabolic Vigor temperature. Within the next hour he receives 8 damages. Then the sorcerer uses Fiendish Vigor for 5 temp hp.
What happens now:
A. The sorcerer earns 5 temporary hp and can earn hp temp repeatedly during a match as long as the damage has eliminated the current temporary hp.
B. The 5 temp hp replace the previous 8 temp temp and the sorcerer loses 3 real hp.
You can cast False Life on you at will as a first level spell, without spending a spell space or material components.
Duration: 1 hour.
Reinforcing yourself with a facsimile of necromantic life, you gain 1d4 + 4 temporary hit points while it lasts.