Editing Macchiato Monsters: The Stygian Library (section)

====How Does Combat Work?====
There is no initiative, and monsters and NPCs usually don't take turns of their own. Instead, the GM states at the top of the round exactly what the opposition will do and to whom, each PC gets a turn to act, and the final results are decided by the rolls of the PCs.

On your turn, you can attack, run across a room, cast a spell, reload a gun, or anything feasible within a few seconds. Each turn, you'll roll the D20 once if taking action: STR to swing a sword, DEX to throw a dart, CON to run despite poison, INT to find a hiding place, WIS to channel a spell, CHA to intimidate someone, etc. If you succeed and were attacking, roll damage for your attack. If you fail and were being attacked, you're hit and take damage. (If you were casting a spell, it goes off when you succeed; if you were being spellcast at, it deals any damage when you fail, and you may get a second stat roll to 'save' against additional effects.)

The first time you take damage in a situation, roll your Armor Δ if any. The result is how much total damage your armor can soak in this situation before it goes to your HP. If you have a shield, you can sacrifice it to negate all damage from one attack, if the shield could physically be used in that way.

If an enemy takes a powerful blow or is intimidated by a CHA check or flashy spell (for example,) they roll a Morale Δ to see if they retreat, double down, change tactics, or flee in panic. They don't want to die any more than the PCs do, probably.

Getting out of combat by fleeing takes a DEX check, which may require dropping something heavy to avoid rolling with disadvantage. Outside of combat, evading pursuit or chasing someone down is a CON check. In the Stygian Library, fleeing into the corridors risks getting lost and ending up somewhere you didn't plan.

Traits don't give advantage on combat rolls. Firing from cover or a surprise attack might give advantage, or using a shield to protect against incoming missiles, or expending an appropriate special ability like 'Backstab' or 'Martial Arts.'

You will often have disadvantage in combat, though. Most often this happens when melee attacking an opponent with higher HD than your HD. (Not your level.) To reflect relative combat skill, PCs roll with disadvantage when attacking an opponent with more HD in melee. This can be avoided by ganging up: everyone attacking the same target at once adds their HD together for this comparison, and if their HD is equal to or greater than the target's, they each roll normally. Monsters can also gang up in this way: four HD 1 scrublings in a phalanx count as HD 4. Missile attacks do not suffer disadvantage on higher HD targets, but also do not add to HD for ganging up: it's melee only.

Here's how a combat round should look in PBP:
*1. Start of the round: DM describes the situation, the threats, the monsters, and what exactly they are doing (for example "two sword attacks on the wizard.") The stakes should be made clear to the players so it's clear what will happen on a roll.
*2. Any PC posts to describe what they do, checking to be totally clear about risks and possible consequences if needed, and rolls a stat check to see if they succeed. If they have a henchling, they may have it act as well, rolling its Δ if it's taking a risk. Damage is dealt and consequences are described, probably by the PC, possibly the DM if the situation has changed significantly.
*3. Any other PC posts, as in step 2, until all PCs have acted.
*4. If any monsters or NPCs haven't done anything this turn, the DM may have them act now, rolling out-of-sequence checks for any PCs if they're affected.
*5. End of the round. DM updates the situation and starts a new round.