A PC is allowed to use a reaction on another player’s turn or a monster’s turn. However, there aren’t many abilities that use a reaction, so most players won’t be able to take advantage of their reaction all that often.
Opportunity Attacks
When a person or computer is presented with an opportunity, they may take it without thinking. This can be dangerous, as the person or computer may not be aware of the consequences of their actions. ..
An Opportunity Attack is a special attack that you can only take if an enemy moves out of your reach when you are wielding a melee weapon.
This usually occurs because an enemy is trying to run away or because they are trying to get past you.
Most melee weapons have a reach of 5 or 10 feet.
If a PC leaves their range, enemies are allowed to take an opportunity attack.
It’s possible to avoid taking an opportunity attack by using the Disengage action, or through other special abilities. ..
Other Abilities Using a Reaction
Most abilities that use a Reaction are granted by class or subclass features, spells, or feats.
- “I’m not sure what you’re talking about.”
- “I don’t know what you’re talking about.”
When a PC has prepared an action in advance, such as shooting a bow when an enemy comes within range, the Ready action can be used to trigger that action.
If you are riding a mount and if that mount is knocked prone, you can use a reaction to dismount and land on your feet.
When casting a spell, you can identify it as it’s being cast (an optional rule from Xanathar’s Guide to Everything) with an Intelligence (Arcana) check of DC 15 + spell level. ..
What is Action Economy?
Action economy is a term to indicate how effective a player is at accomplishing multiple things during each round. This means that the player can complete more tasks in a given round than would be possible if they only attempted to do one.
Many skilled players try to use both their reaction and bonus action, which can make their characters more effective and more deadly in combat. ..
Players can use class features, feats, and spells to improve their action economy. Class features include: -Athletic ability -Combat Reflexes -Extraordinary Strength -Invisibility -Languages: Common, Dwarven, Elven, Gnome, Halfling, Orcish
A popular feat is Polearm Master, which allows a PC to make a bonus action attack on their turn and take an opportunity attack when an enemy moves into their range.
This feat is great for action economy because it gives players a bonus action and a reaction option, which can let them make up to three times as many attacks as they normally would. ..
Reactions can be used as characters gain levels, to create interesting and unique interactions. For example, when a character reaches level 10, they may start to learn new spells. This can lead to interesting conversations with their friends and enemies, as they try to figure out how to use the spells they’ve learned.
Spells that require a reaction, like shield, absorb elements, hellish rebuke, feather fall, and counterspells, are used more often in certain situations. ..
In each of these cases, a specific event needs to happen in order for the spell to be cast. For example, an enemy needs to attack on you in order to cast Shield, whereas an enemy needs to damage you in order to cast Hellish Rebuke.
Rogues are masters of the Action Economy, because their Cunning Action gives them several bonus actions abilities, and Uncanny Dodge lets them use a reaction to take half-damage from one attack each turn, provided the attack is visible to the rogue. ..
Rounds and Turns in 5e
In 5e, every character has one action and one bonus action they can use on their turn, and one reaction that they can use during each round of combat. This means that characters have a lot more control over their actions than in previous editions of the game. ..
A Round is made of a series of Turns, each one adding an increment to the previous turn.
Each player gets their own turn, during which they can move and take an action. If they have a bonus action, it is added to their normal action.
Initiative is rolled for each character, and the order of Turns is determined by the result. Enemies get one or more Turns where they can move and act. ..
Since a Round is made of many Turns, a player can use reactions on other characters or during an enemy’s turn if there are triggering effects.
A player can use a reaction on their Turn, provided there’s a triggering effect. For example, if you have the ability to fire an arrow at a creature that is adjacent to you, but the creature is immune to ranged attacks, then you can fire an arrow at it instead.
If a player moves and takes an Opportunity Attack, they can use their reaction to cast the Shield spell. However, they’re not allowed to do this if they’ve already cast a Bonus Action spell, because the rules for casting a spell using a bonus action state that “you can’t cast another spell during the same turn, except for a cantrip with a Casting Time of 1 action.”
A wizard can cast a spell using a regular action and a reaction during the same turn by using his reaction.
Some Basic Reaction Rules
If you have not used your reaction before your turn starts, you lose the previous reaction and start anew. If you use your reaction before your turn starts, it is considered used and cannot be used again for that round. ..
Your reaction starts at the beginning of your turn.
PCs and enemies are not allowed to use a Reaction if they are Surprised at the beginning of combat until the end of their first Turn. ..
Players are not allowed to move or take an action until the end of their first turn. ..
The Bottom Line
Don’t be discouraged if you can’t seem to use your Reaction all that often. There are plenty of other ways to express yourself.
As you level up, you may find that some of the bonus actions available to you are more useful than others. To maximize your potential as a fighter, for example, it may be helpful to learn the following bonus actions: -Bash: This action can be used to deal damage to an opponent. -Block: This action can be used to protect yourself from an attack. -Crouch: This action can be used to move quickly and quietly.
Some of the newer subclasses (such as those in Xanathar’s Guide to Everything or Tasha’s Cauldron of Everything) are slightly more likely to have reaction abilities than the subclasses in the Player’s Handbook.
Spellcasters should seriously consider taking at least one reaction spell if they have a decent choice. However, casting a spell using a reaction still uses up a spell slot, so you probably don’t want to overuse reaction and bonus action spells. ..
