Spell Master

General Feat (Prerequisite: Level 4+)

You gain the following benefits.

Ability Score Increase. Increase one ability score by 1, to a maximum of 20.

Residual Energy. Immediately after you take the Magic action, you can use a Bonus Action to gain Temp HP. The amount equals your spellcasting modifier. (This HP does not stack, each activation is a new source of temp hp).

Reactive Cast. You can take a Reaction to cast one spell against a creature that enters the range of a spell you have that is capable of targeting/affecting the triggering creature, as well as when a creature exits melee range.