Yes, this is highly imbalancing
You most frequently face enemies between PL-2 and PL+2.(1) The game provides the following typical AC values:
- AC 13 is considered Low for a level 0 enemy.
- AC 24 is considered Extreme for a level 4 enemy.
A level 2 rogue should have a +1 weapon, granting them a +9 to hit. This gives us a typical range of 4 to 15 on the d20 to hit most enemies, or 2 to 13 on the d20 to hit off-guard (with only one source of off-guard). At this point, we can completely ignore the original to-hit value - all that matters is which number on the d20 you need to roll.
In PF2e you score a critical hit if you meet or exceed the target's AC+10, or if you roll a natural 20 (assuming the total is enough for a hit). This means that you can never have more than a 50% chance to hit; additional bonuses apply to your crit chance. As a baseline:
| Min d20 that hits |
% hit |
% crit |
% base dmg |
| 2 |
50% |
45% |
140% |
| 3 |
50% |
40% |
130% |
| 4 |
50% |
35% |
120% |
| 5 |
50% |
30% |
110% |
| 6 |
50% |
25% |
100% |
| 7 |
50% |
20% |
90% |
| 8 |
50% |
15% |
80% |
| 9 |
50% |
10% |
70% |
| 10 |
50% |
5% |
60% |
| 11 |
45% |
5% |
55% |
| 12 |
40% |
5% |
50% |
| 13 |
35% |
5% |
45% |
As you can see, your chance to hit increases until reaching 50%. At that point, your chance to crit increases instead. Base damage is the damage you do on a hit (10 [2d6+3] for a level 2 rogue with Sneak Attack). If a row says you deal 120% of base damage, that's 10*1.2 = 12. The percentage of base damage assumes that crits are merely double damage, ignoring the Deadly or Fatal traits.
Stacking off-guard
So given that baseline, how much of an increase in damage is adding a second (stacking) off-guard?
| Min d20 no bonus |
% hit w/bonus |
% crit w/bonus |
% base dmg w/bonus |
Dmg increase |
| 2 |
40% |
55% |
150% |
7% |
| 3 |
45% |
50% |
145% |
12% |
| 4 |
50% |
45% |
140% |
17% |
| 5 |
50% |
40% |
130% |
18% |
| 6 |
50% |
35% |
120% |
20% |
| 7 |
50% |
30% |
110% |
22% |
| 8 |
50% |
25% |
100% |
25% |
| 9 |
50% |
20% |
90% |
29% |
| 10 |
50% |
15% |
80% |
33% |
| 11 |
50% |
10% |
70% |
27% |
| 12 |
50% |
5% |
60% |
20% |
| 13 |
45% |
5% |
55% |
22% |
A few points about this table:
- If you hit an enemy with one "stack" of off-guard on a 3 or lower, then lowering its AC further actually reduces your hit chance (in exchange for more crit chance).
- The damage increase is the percent increase in damage, not the percentage point increase. Going from 50% base damage to 60% is a 20% increase in damage.
But wait, there's more!
As your level increases, it becomes even easier to stack multiple sources of off-guard. The critical specialization effect of swords (accessible at level 5 for rogues and fighters) makes an enemy off-guard on crit. Combining flanking, a Feint, crit spec, Snagging Strike, and blinding the enemy could result in a -10 to AC - an entire degree of success!
So is this imbalancing?
In the majority of fights, stacking two instances of off-guard increases your damage by 20-30%. That's more than the typical increase in damage due to gaining a level!
Also, consider what it normally takes to effectively reduce an enemy's AC by 2 (after it's already off-guard):
- Spend an action and critically succeed on a Demoralize. Reduces over time and can't be reapplied by the same ally.
- Spend two actions and a 1st-rank spell slot to cast befuddle and have the enemy fail. Lasts 1 round.
- Spend two actions and a 6th-rank spell slot to cast heroism on you.
- Spend an action to Prepare to Aid, a reaction, and critically succeed on a DC 15 check. At low levels, this is certainly not guaranteed.
Some of those include other benefits, but it's telling that the game provides no reliable, repeatable, resourceless means of further reducing effective AC, particularly at low levels. Even when Aid becomes automatic, it still takes an action and a reaction.
So yes, this is extremely powerful even if you can only stack two instances. Given how tight the math of 2e is, I would not recommend keeping this house rule.
How should a new group proceed?
There are several factors that lead to low level play with new PF2e players feeling particularly tough:
- The baseline difficulty of an encounter tends to be higher. When D&D 5e says that an encounter is Hard (the second highest difficulty), that typically translates to Not Completely Trivial. When Pathfinder 2e says that an encounter is Severe (also the second highest difficulty), that typically translates to Might TPK Without Proper Tactics.
- By design, 2e emphasizes tactical decision making and teamwork. Fights where players are learning the system and thus not optimizing their actions will feel more difficult.
- Low level play is swingier with each hit dealing a larger percentage of the opponent's health (on both sides of the screen).
So how would I ease the learning process without imbalancing the game?
- Have the GM stick to Low and Moderate encounters for now. The number of enemies also matters: "Encounters are typically more satisfying if the number of enemy creatures is fairly close to the number of player characters."
- Take some time as a group to figure out a few viable "third actions". That is, the actions you can take in addition to casting a spell or moving and attacking - Raise a Shield, Demoralize, Bon Mot, Feint, etc. The Rules Lawyer has a helpful video on third actions and 1dM covers The Power of +1.
- As levels and player experience increase, the occasional Severe encounter can be sprinkled in for important story moments, though the GM should still be cautious about using one big enemy to prevent combat from turning into a slog.
(1) PL means Party Level, so a PL-2 enemy is two levels lower than the party, while a PL+2 one is two levels higher.
