A list of some of the things that are new or specific to 5E.

Rests
There are two types of Rest that you can take in 5E - Short and Long.

A Short Rest takes one hour in-game, during which you do not strenuous activity. You can eat, sleep, talk, read, tend wounds. That's about it.

During a Short Rest, you can spend your hit dice to restore hit points to your character. You can spend any number of your available hit dice, and the dice you have correlate to the classes that gave them to you. So a Fighter 1/Rogue 1 for example has a total of 2 hit dice for being a level 2 character, but their hit dice are 1d10 and 1d8. So if they wanted to restore their HP they would decide which of the dice they wanted to spend during that short rest, if any. They may spend the d8 first, and save the d10 for later. You can also choose to roll one die at a time, apply the resulting healing, and then decide whether or not you want to spend another die, and so on.

Some classes and races also have abilities that they can utilize during a Short Rest, or abilities that recharge during a short rest. For example, the Wizard has an ability called Arcane Recover that allows them to restore some of their expended spell slots during a short rest. Other examples include the Druid's Wild Shape ability which restores all uses during a Short Rest, and the Warlocks spell slots which all restore during a Short Rest.

You can also spend a short rest studying a magical item in order to determine its magical properties. This works similar to how the Identify spell has in previous editions, though it will not tell you everything about a complex magic item. It will tell you that this sword is a +1 Longsword, or those boots are Boots of Flying. It has limitations, but for the most part that's how you identify magic items in this edition.

A Long Rest takes 8 hours in-game, 6 of which have to be spent on sleeping (3 meditating for elves). Even if you're playing a character who does not need eight hours of sleep/rest to feel refreshed, in order to gain the effects of a Long Rest you must spend eight hours on the activity. If a long rest is interrupted by a strenuous activity that lasts for at least 1 hour, the long rest is cancelled and you must begin again in order to gain any benefit from the rest.

At the end of a Long Rest, your character heals back to full hit points, you restore all of your expended spell slots or special ability uses, and you restore 1/2 of your total hit dice, rounded up (a level 7 or 8 character restores 4 hit dice, for example). Any effect that is replenished by a Short Rest is also restored by a Long Rest.

Advantage
Advantage is a new mechanic in 5E that allows you to roll two d20's when making various rolls, and choosing the higher of those two rolls to actually use. Disadvantage works exactly the same way, except that you have to use the lower of the two rolls. So if your two d20's result in a 5 and a 17, Advantage allows you to use the 17 while Disadvantage forces you to use the 5.

These mechanics do not stack, so no matter how many different sources give you Advantage, you either have Advantage or you do not, you can't have double-advantage. If you are in a circumstance where you would have both Advantage and Disadvantage on a task, then both effects are canceled and you just roll a single d20. This is true even if you have multiple sources of Advantage and only a single source of Disadvantage.

Inspiration
Inspiration is another new mechanic, which is a reward that can be given out by the DM. Inspiration is a one-use ability that will give you Advantage on a d20 roll.

(Not to be confused with a Bard ability called Bardic Inspiration, which grants you a bonus to a d20 roll.)
This message was lightly edited by the GM at 14:07, Tue 17 July 2018.

Standard Critical Hits

In 5E, scoring a critical hit (getting a natural 20 on your attack roll, without modifiers) with a weapon or spell means that you roll twice the number of dice for the attack.

For example, a Rogue with Dex +3 wielding a Rapier does 1d8+3 damage, so on a critical hit it would deal 2d8+3 damage (number of dice gets doubled, but modifiers do not).

If that same Rogue is also able to roll Sneak Attack damage on that attack, then it would normally deal 1d8+1d6+3 damage, so on a critical hit it would deal 2d8+2d6+3 damage.

If that same player also had access to the Warlock's Hex spell, then a normal hit would be 1d8 (rapier) +1d6 (sneak attack) +1d6 (hex) +3 (dex), and a crit would be 2d8+2d6+2d6+3.


House Rule
Here I am going to introduce a House Rule, where I make a change to existing rules to better suit the kind of game I want to run.

When you roll a natural 20, it's supposed to be really cool both for the narrative as well as the payoff for the player. Well, there's nothing less cool than rolling that natural 20 for your attack and then rolling your damage dice and having them both roll up as 1's.

So, when you score a critical hit, instead of doubling your dice for your damage, I want you to roll damage like you normally would for a non-crit, and then add a number to the dice roll equal to whatever the maximum for the normal damage dice would be.

So back to the examples above.
Rogue (Dex 3) with a rapier - Normal damage is 1d8+3. Crit damage is 1d8+11 (3 Dex + 8 from rapier's d8)
Same Rogue, with Sneak attack - Normal is 1d8+1d6+3. Crit damage is 1d8+1d6+17 (3 Dex +8 rapier, +6 sneak)
Same Rogue, with Sneak, with Hex - Normal is 1d8+2d6+3. Crit damage is 1d8+2d6+23 (3 Dex +8 rapier, +6 sneak, +6 hex)

This rule works both ways, meaning you will deal some crazy damage to your opponents when you roll natural 20's, but they will be doing the same to you as well.

D&D runs off of what we call a "d20 System" which means that the 20-side die is the core of game system. The majority of the rolls you make in D&D will be done with a d20, with modifiers added to it for increased or decreased chance of success. For the most part, any time you roll dice for anything other than damage or healing, you're going to roll a d20.

Here are some terms for you to familiarize yourself with if you are new to D&D.

Initiative (d20): this mechanic determines the order of play during combat. The higher your initiative, the sooner you get to act. Initiative is a Dexterity check, so when you roll the d20 you add your Dexterity modifier to the result.

Attack (d20): Attack rolls are used for all forms of attacks (melee, ranged, and spell), to see if your attack successfully damages your target. When you make an attack roll with a weapon that you are proficient with, you add your Proficiency modifier to the roll (+2 for level 1 characters). You also add either your Strength modifier (melee weapons, optional for thrown weapons), your Dexterity modifier (ranged weapons, optional for thrown weapons, optional for melee weapons with the Finesse property), or the modifier for the spellcasting ability (Int for Wizards, Fighters and Rogues - Wis for Clerics and Druids - Charisma for Bards, Sorcerers and Warlocks). Rolling a natural 20 on an attack means that you automatically hit regardless of the target's armor class, and you deal increased damage.

If you are not proficient with a weapon, you still add modifies for the ability score, but you do not add your proficiency modifier.

Skill Checks (d20): Skill checks are used to have your character accomplish various tasks such as climbing, swimming, hiding, picking locks, crafting, applying a disguise, lying successfully, character knowledge, and so forth. When you are proficient with a skill (either from your race, class, background, or feats) you get to add your proficiency bonus to the d20 roll. In addition to that, you also add the modifier from whichever attribute is tied to that particular skill. Rolling a natural 20 on a skill check is an automatic success.

Ability Checks (d20): Ability checks are very similar to Skill checks, and work exactly the same way. Sometimes a particular skill is not quite right for an action that your character is performing, so rather than asking for a skill check, you will be asked for an Ability Check. In these cases, you will roll 1d20 and add the modifier for the ability in question. Rolling a natural 20 on an ability check is an automatic success.

Saving Throw (d20): Saving Throws are a form of active defense targeting different abilities (Str, Dex, Con, Int, Wis, or Cha). When you make an attack, you are doing active offense, meaning that you are making a roll to actively overcome the target's defenses (armor class) in order to succeed on the attack. Saving Throws are the same concept, just in reverse. So instead of trying to meet-or-beat the opposing defense, you are trying to meet-or-beat the incoming offense. These rolls will most often come in response to spells or traps. If you are proficient in a particular type of saving throw (determined by your class) then you add your proficiency bonus to the roll. All saving throws are tied to a specific ability (Str save, Dex save, etc), so you also add the corresponding ability modifier. Rolling a natural 20 on a saving throw is an automatic success.

Death Saving Throw (d20): Death saves are a special roll made when your character is at 0 HP and dying. Each round that you are at 0 HP, and not stabilized, you have to make a Death save. Death saves do not have any modifiers at all, you simply roll a d20. If the roll is 10 or higher, you succeed. Otherwise you fail. The goal with death saving throws is to roll 3 successes before you roll 3 failures, so best 3 out of 5. If you get 3 successes then you stabilize yourself and no longer have to make death saving throws. If you get 3 failures before you stabilize, then your character dies. Rolling a natural 20 on a death saving throw not only stabilizes you, it also restores you to 1 HP and brings you back to consciousness.

Ready Actions:
There is a mechanic you can use in 5E where you ready an action, waiting for a specific event to trigger it. In 5E if the trigger for your action does not take place, then the action is lost. If your readied action was to cast a spell, then the spell slot you used to cast it is lost as well, and the spell has no effect.

Here are some examples of readied actions and how they work.

Bob: "I'll ready action an attack with my longbow whenever I see an enemy step out of the fog."
Action: Ready - attack with longbow
Trigger: enemy steps out of the fog, into view

If an enemy does step into Bob's view before Bob's next turn, then as soon as the triggering event happens, Bob gets to take his attack. If the enemy was going to move and then act, the movement was part of the trigger, so Bob would attack before his target does because his attack was already readied.

Fred: "I'll ready an action to cast Sleep as soon I can catch all 4 goblins without hitting Jessica with it"
Action: Ready - cast sleep
Trigger: positions change to where I can hit the goblins but not Jessica

If Jessica doesn't move, or the goblins spread out, or anything else prevents the 4 goblins from being hit without hitting Jessica, then the triggering event never happens so the spell never gets cast. However, since Fred readied the spell, he loses the spell slot as though he had cast the spell. If Jessica did move out of the way, then as soon as she finished her movement, the Sleep spell would be cast and resolved, and Jessica could then use her action to stab a now-unconscious goblin.

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In previous editions of D&D, you could set a contingency, like, "cast the spell when I can see a target, but if not then just heal myself instead". 5E doesn't have contingencies. Either your action gets triggered, or your action gets wasted, that's it.
This message was last edited by the GM at 02:02, Thu 19 July 2018.