Reactive

You've trained your reflexes and techniques, so you can always have a trick up your sleeve when you're in trouble, by acquiring this feat you can use your reaction to act during another creature's turn, but only after the creature has completed an action, move, or used the bonus action. As you will be doing a quick action, your effectiveness is reduced, as shown in the options below:

Attack — The damage die will have no ability modifier.

Cast a spell — The spell's level must be less than or equal to half its proficiency bonus

Dash — Can only move half of the movement

Dodge — Only attacks will have disadvantages

Help — Gives the friendly creature advantage on the next attack against a creature within 5 feet of you.

Hide — Testing is done at a disadvantage.

Search — Testing is done at a disadvantage.

Uses an object — Can only be used as object interaction.

Other uses can be had with the consent of the game master.