Never let it be said that the only thing I do is try to kill my PCs — I also rip off other people’s ideas. The system there is for companions, named and DM-provided characters which function a little like an equipped magic item. It’s an idea so nice, I gotta try to riff on it myself.
A companion is an opportunity to refit a few of the softer D&D rules work for us — especially inspiration.
As a reminder, you usually get inspiration when you play to your character’s ideals/bonds/flaws in an interesting way; unfortunately, compared to Fate or similar games, the implementation here is pretty lackluster. The guidance is basically “be compelling and the DM will give it to you; have inspiration and you can give it to others as though you were the DM”. You can expend inspiration when you make an attack, save, or check; it gives you advantage on that roll.
The problems with this are well-recorded; the inspiration is granted with little more direction than “be interesting”, and expended “when you need the bonus”, so it doesn’t really drive the story — in theory, at least, you get inspiration for your ideal as easily as your flaw.
First, a slight modification: you do not “have inspiration”, you “have inspiration in one of your ideals, bonds or flaws”.
Let’s see what adding other people to the mix can do.
Take the (unintelligent) mount rules as a base; in other words, you share a space with your companions and they don’t really get actions of their own, but instead take their turns as a part of you taking yours. In particular, their contributions are modeled as giving your character new capabilities.
Your companions have their own ideals, bonds and flaws (IBFs). Indulging the companion in a IBF while they are on screen inspires that IBF just as it would a PC. The PC may also transfer inspiration from one of the PC’s IBFs to the companion’s IBF. In either case, a given companion’s IB or F can only be inspired once per session.
Once per turn, the PC may take (atop their normal complement of actions) a companion action (similar to a legendary action), selecting from the menu of companions and their actions available to them; using a companion’s companion action discharges the indicated number of IBFs. Some companion actions are marked as “reactions” — these consume a companion action as indicated, but happen at the time indicated, rather than as a standalone legendary-like action.
You can draw companion IBFs from the ones associated with the backgrounds below (listed in the PHB) or from the tables for this purpose in the DMG, page 89. Companions with a secret agenda (a public and a private face) will still use this system openly with their false front, but the DM should track their private character as a more full NPC. Otherwise, if the companion is operating independently, use the parenthetical statistics.
Acolyte (acolyte + insight, religion, and 2 languages)
Cast a cantrip (1 point): You can cast one of your cantrips (or guidance).
Tend wounds (1 point): At the end of this short rest, all creatures spending at least one hit die recover an additional 1d6+their level hit points.
Cast a spell (2 points): You can cast one of your first or second level spells (or cure wounds 1/day).
Charlatan (bandit + deception, sleight of hand, disguise, forgery)
Suggestive patter (1 point): One non-hostile creature who has been listening to you talk for 1 minute or more is exposed to a suggestion (save DC 8 + your proficiency + your charisma modifier).
Dip (1 point): You lift an object off the attacker’s person which could reasonably be pickpocketed.
Violent dodge (2 points, reaction to being missed with a melee attack): The attack is repeated against a target of your choice which would have been a valid target of the initial attack.
Criminal (bandit + deception, stealth, a gaming set, thieves’ tools)
Escape (1 point): You immediately make an escape check against one grapple or restrained condition, and may move up to half your speed without provoking opportunity attacks.
Hurt (1 point, reaction to hitting an enemy with advantage): Deal 1d6 extra damage per point of proficiency.
Mislead watcher (2 points): You may move half your speed and then hide behind the barest scrap of cover. Normal line of sight rules resume as each other creatures’ turns begin.
Entertainer (commoner + acrobatics, performance, disguise kit, musical instrument)
Echo (1 point, reaction to a creature succeeding at a save and becoming no longer frightened of or charmed by you): That creature is still frightened (or charmed), subject to the same effect until the beginning of its next turn.
Tumble (1 point, or as reaction to a trap or a fall): Move your speed, taking half damage from opportunity attacks, traps and falls until the start of your next turn.
Inspire (2 points): Give a target who can see and hear you within 60 feet an inspiration die (per the bard class feature); the die size is based on your proficiency bonus; +2 = d4, +3 = d6, and so on up to +6 = d12. This can be added once to one ability check, attack roll, or saving throw; recall a character may hold only one inspiration die at a time.
Folk hero (commoner + animal handling, survival, a tool, land vehicles)
Hard work (1 point): You heal 1d10 hit points plus your level and lose one level of exhaustion.
Good, clean living (1 point, reaction to becoming frightened, charmed, or poisoned as the result of failing a saving throw): You succeed on that saving throw instead.
Hear the people’s cry (2 points): You and any number of allies who can see and hear you within 60 feet gain can make a melee weapon attack with disadvantage as a reaction.
Guild artisan (noble + insight, persuasion, a tool, a language)
Just the thing (1 point, 2 points or 3 points): Produce an item from the PHB equipment list of up to 50 gp in value (500 gp in value, 5000 gp in value); if it weighs more than 10 pounds, you instead know where to obtain the item with no trouble.
Assay quality (1 point): Cast identify.
Hermit (cultist + medicine, religion, herbalism kit, a language)
Strange insight (1 point): One creature within 30 feet that you can see and hear makes a deceit check opposed by your insight; if you succeed, you learn a secret about it.
Seek seclusion (1 point): Move half your speed away from one creature without provoking opportunity attacks from anyone.
Foretell (2 points): Roll a d20. You may substitute that for any d20 which would be rolled by any character within 60 feet before the start of your next turn.
Noble (noble + history, persuasion, a gaming set, a language)
After you! (1 point): A creature of your choice within 30 feet that can see and hear you can use its reaction to move half its speed and make a melee weapon attack.
Leadership (2 points): For the next minute or until you are incapacitated, you may use your reaction to give other creatures that can see and hear you within 30 feet a bonus d4 to their attacks and saving throws.
Majestic presence (2 points): All creatures of your choice within 30 feet that can see and hear you make a wisdom save DC 8 + prof + cha or are charmed or frightened for 1 minute (your choice, save at the end of each turn). Consumes concentration.
Outlander (tribal warrior + athletics, survival, a musical instrument, a language)
Hunt and gather (1 point): Provide food, water, shelter and supplies for 10 people.
Invoke idol (1 point): You cast guidance or hunter’s mark.
Farstrider (1 point): You move your speed, ignoring difficult terrain.
Sage (acolyte[1/4] + arcana, history, two languages)
Divine (1 point): You cast guidance, detect magic or detect evil and good without expending a spell slot.
Augur (1 point): At the end of this short rest you can cast comprehend languages or augury without expending a spell slot.
Advise (2 points, reaction to failing a saving throw against a spell or magical effect): Succeed on that saving throw instead.
Sailor (bandit[1/8] + athletics, perception, navigator’s tools, water vehicles)
As some other type: sailors give bonuses dependent on their role on the ship (often criminal, soldier, or peasant hero).
Soldier (guard[1/8] + athletics, intimidation, a gaming set, land vehicles)
Defend (1 point, reaction to getting hit): Add your proficiency to your AC until the start of your next turn, including against the triggering attack (which may now miss).
Watch (1 point): Make a perception check.
Attack (1 point): Make a weapon attack.
Urchin (commoner + sleight of hand, stealth, disguise kit, thieves’ tools)
As some other type: urchins often function as criminals, charlatans, or entertainers.
Since these companions just sort of drag along with your character, they occupy a sort of non-space in the game: they don’t get directly attacked, they don’t need to be exposed to danger, etc.
If that’s a little too unrealistic for you (“since my PC is bleeding on the floor, I have Yinkle drag me back behind cover, since he should still be fine!”), then you can use the recommended stats (or substitute stats, for better companions) and make it the PC’s duty to track their welfare. That’s pretty heavy handed, though, since I imagine most of the time their damage is only really coming from area effects, and you’re not REALLY boosting the opposition to reflect the real number of characters in the scene.
Thus, you could “fake it” by saying that each companion takes the same damage as their PC does from area attacks, and that the PC can choose to funnel the blow which would drop the PC to 0 hit points to one of the companions instead; then, if the PC would prefer to have Yinkle drag them behind cover, they can instead have Yinkle eat the blow.
Be careful of this second option: villains should be surrounded by guards, right? Once they do that, why aren’t the guards eating their death blows?
Why do these rules use _your character_ as the originator for the actions? Because per these rules, your companion isn’t really there; they just provide a palette of actions, really.
Henchmen vs hirelings: Because you can randomly generate these guys, and their effects explicitly are NOT an additional set of hit points in the encounter, it seems very reasonable to treat these as purchasable assets. 2gp per day, maybe a modest downpayment like 20gp for the first week’s pay; if you want to do a dungeon, 5gp per day and a 50gp downpayment still seems very reasonable to me: you still have to hit the companion’s IBFs to use them.