You have learned how to react faster than most can think, and this carries over to your combat capabilities with the following benefits:
- Increase your Dexterity score by 1, to a maximum of 20.
- As a free action, you may take an additional reaction this round. Readied actions can still only be taken once. You can use this feature up to three times per rest. You regain all expended uses of it when you finish a short or long rest.
- You can use your reaction to gain advantage on a Constitution saving throw to maintain your concentration on a spell.