Blazing Terminus

When you cast this spell, your current hit points becomes equal to 10.

For the duration, if any effect other than this spell would cause you to gain or lose more than 1 hit point, you instead gain or lose only 1 hit point. Additionally, whenever you use your action to cast a spell of 4th level or lower, your current hit points becomes equal to 5 minus that spell's level, then you may immediately cast a 1st level spell with a casting time of 1 action using your bonus action. If you end your turn without casting a leveled spell, you gain 1 hit point.