Retainers and Hirelings

Introduction

If the party ever has an NPC assisting them during an adventure, that NPC will likely take on the role of a retainer or hireling. These characters assist as much as they can in combat, but are not as strong as a player character, and certainly not as cool! They are also much simpler to run than an entire character. Any retainers or hirelings will use the rules detailed on pages 69-72 in Strongholds and Followers, but I summarized those rules below.
Retainers and Hirelings have the exact same mechanics, but I refer to them separately because Hirelings are typically being paid while retainers are often loyal to a particular player character. I will simply refer to both of them as retainers from here on.

Retainer Rules

Example Statblock

Knight-Sorcerer
Armor	Heavy (AC 18)
Primary Ability	Strength
Saves	Strength, Constitution
Skills	Arcana, Insight
Signature Attack	Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8+4) slashing damage
Special Actions
3rd-level (3/day)	shield
5th-level (3/day)	thunderwave
7th-level (3/day, bonus action):	Spellblade. The knight-sorcerer casts firebolt.

Health Levels, not Hit Points

Instead of hit points, retainers have health levels equal to their level. Anytime they are hit by an attack, they roll a Constitution saving throw, where the DC is the average damage of the attack (listed in the stat block, the DM will know). If they succeed, they take no damage. If they fail, the lose one health level per die of damage (so if they roll 2d6 for damage, they lose 2 health levels). If they lose their last health level, they fall unconscious and use the normal rules for dying.

Healing

Retainers regain a health level after each short rest. When being healed by spells or abilities, they regain one health level for each die of healing used. They regain all health levels on a long rest.

Initiative

Retainers act on their player character's initiative.

Armor Class

There are only three levels of armor for a retainer: Light (AC 13), Medium (AC 15), Heavy (AC 18). This is detailed in their stat block.

Abilities and Skills

A retainer has a primary ability and various skills. On any normal ability check, they roll a +3. If the check uses their primary ability, they get an additional +1. If it's a skill check using one of their skills, they instead get an additional +2.

Saving Throws

The retainer's stat block will list one or more saves they have. On any normal save, they roll a +3. If it's with one of the saves on their card, they instead roll a +6.

Actions

Retainers can take all the same actions that a PC can do. They also have a signature attack they can make each round. They might also have some special actions available to them. Special actions can only be used once every 10 minutes.

Attacking

If the retainer's player character hits an enemy, their retainer automatically hits with their signature attack, even if they are attacking a different target. This is intended to reduce the total number of rolls a player has to make on any given turn. If the player character misses with their attack (or simply doesn't attack), the retainer may still roll to attack. They get a +6 to all attack rolls.