When battle begins, apt adventurers don't wait to be hit by the enemy—they take defense into their own hands by dodging, blocking, and parrying.
This chapter introduces defense rolls and saving attacks, putting defense back into player control.
Whenever the GM would normally make an attack roll against a player character, that player may instead make a defense roll to see if they can avoid the attack—dodge, duck, dip, dive, and dodge your way to success.
Roll a d20 and add your AC—this your defense roll. The opposing DC is 22 plus the attacker's attack bonus.
Defense Roll: d20 + your AC
DC: 22 + attacker's attack bonus
If your defense roll equals or beats the DC, you avoid the attack. If you fail, however, the attack hits you.
Advantage: If your attacker would have advantage on their attack, apply disadvantage to your defense roll—and vice versa if your attacker would have disadvantage.
If your defense roll comes up as a natural 1, it's a critical fail—you are critically hit by the attack. If you roll a natural 20, it's a critical success—you defend with style.
Critical Ranges: If your attacker would normally score a critical hit on a roll of 19 or 20, then their attack is a critical hit on a 1 or 2, and so forth.
Here we see Valiant, Sarien, and Clanda being attacked by three orcs. Where the GM would normally be rolling attack rolls for the monster, the players instead make defense rolls to avoid the incoming attacks.
If you are a divination wizard, it's easy to use your Portent ability with Active Defense.
When you give a portent result to someone making a defense roll, they may use either the normal value or the d20-inverse value (calculated as 21 - portent value).
Emwyn, a divination wizard, has a portent result of 3 remaining. When attacked, Emwyn must make a defense roll. He chooses to use his portent instead of rolling, and takes the inverse value of 18 (21 − 3)—Emwyn's defense result is 18 + his AC.
Whenever the GM would normally make a saving throw, the player instead rolls a saving attack to see if they can beat the target's defenses.
When you make a saving attack, roll a d20 and add your normal spell save DC. The opposing DC is 22 plus the target's saving throw bonus. If the spell would affect multiple targets, make a separate attack roll for each—but roll the damage only once for all targets.
Saving Attack Roll: d20 + your spell save DC
DC: 22 + target's saving throw bonus
If your saving attack roll equals or beats the DC, you successfully land your attack.
Advantage: If your target would have advantage on their saving throw, apply disadvantage to your saving attack—and vice versa if your target would have disadvantage.
By default, saving attack spells can't critically hit or miss.
To add the potential for massive damage spikes to your game, allow saving attack spells to deal critical damage.
On a critical hit, roll all of the attack's damage dice twice. On a critical fail, however, the spell has no effect at all—even if it would normally cause an effect on a miss.
Both Sides: When using Massive Damage, apply the rule to both players and monsters for fairness—if players can crit more often, so too can the monsters.
At the end of the GM's turn, it's Clanda's time to shine. Where the GM would normally make saving throws to avoid her Acid Splash, Clanda instead makes a saving attack against each orc.
She rolls her spell damage only once, no matter the number of targets, unless she lands a critical hit as per the Massive Damage variant rule—in which case Clanda rolls extra damage for the affected target.
If you want to use smaller modifiers while playing with Active Defense, try this Small Defense variant.
Defense Rolls: When you make a defense roll, roll a d20 and add your AC minus 10. The opposing DC is 12 plus the attacker's normal attack bonus.
Saving Attacks: When you make a saving attack, roll a d20 and add your normal spell save DC minus 8. The opposing DC is 14 plus the target's saving throw bonus.
Defense Roll: d20 + (your AC − 10)
DC: 12 + attacker's attack bonus
Saving Attack Roll: d20 + (your spell save DC − 8)
DC: 14 + target's saving throw bonus