Low-HP 5e

Some quick ideas on how to lower the HP cap for PCs and NPCs. There's lots of discussion around why you'd want to do this, but some reasons you might consider:

• De-emphasizes combat.
• Emphasizes social solutions and creative problem solving.
• Encourages DM to come up with interesting interactions with NPCs.
• Up the realism.
• Monsters stay monstrous.
• Don't have to worry about balancing encounters.

Some relevant discussion here. I also swear I read a good article about capping HP in LoTFP or other such OSR recently but I can't find it for the life of me.

Note that while these changes should be applied to most NPCs and humanoids if they're being applied to the players, they should not be applied to monsters.

Constitution == Max HP.

Probably the most drastic change. A 1st-level character under this option is likely to be a little tougher than by default, but it's slow going from there. Only by increasing your Constitution score will your max HP increase, and even then it's a soft cap of 20 and a hard cap of 30.

I would probably limit characters to a single HD under this system.

This has the added benefit of being simple to apply to NPCs.

Ability Score Increase == HD.

Every four levels or so, you get another HD. Your max HP increases like the default rules.

This should produce gradual progress, and not require many other changes, but still have PCs with only about a fifth their default HP resources.

For NPCs you could probably just divide their HP and HD by 5 (round up).

Interesting side effect: High-level Fighters will end up with more HD than other classes.

Front-Loaded

You get HD and max HP normally until level 4 or so. Then you stop.

Pretty easy to eyeball this for NPCs. Since there's a cap you could even make a little table of Level/Con Modifier. Like this!

Con \ HD	1	2	3	4+
-2	2	5	7	10
-1	3	7	10	14
0	4	9	13	18
+1	5	11	16	22
+2	6	13	19	26
+3	7	15	22	30

You'll never have to track more than 30 points of damage on an NPC under this approach.

Small Max HP Per Level

Your max HP increases each level, but only by an amount fixed by your class, or your Constitution modifier, whichever is greater (minimum 1).

I'd probably set the per-class level based on a ranking of HD, so:

1. Sorcerer, Wizard
2. Bard, Cleric, Druid, Monk, Rogue, Warlock
3. Fighter, Paladin, Ranger
4. Barbarian

NPCs that use d8 for HD end up with about 40% of their default HP.

Magic Considerations

Under any of these, spells that grant HP increases like aid and heroes' feast become much more powerful. I would consider reducing any increases to max HP based on the spell level, or they'll likely become something the party feels like they always have to cast, and that's not interesting. Aid might grant 2 HP per level of casting instead of 5, for example.

Low-level healing spells remain useful for much longer, which means more high-level spell slots are available for other types of magic.

High-level destructive spells become one of the few hopes of defeating high-level monsters in direct combat, which feels right in a certain kind of game. Wizards and sorcerers become more like the glass cannons of older editions.

Heraldic Beasts

They are tied to the fortunes of a family. As the house gains in size and influence, its beast's HD increases. A new and minor house's beast has 1 HD. The royal family has two or three 10 HD beasts.

https://abookofcreatures.com/2018/01/28/9462/

These creatures appear to sprout from a steel breastplate like an unruly houseplant. They generally drop to all fours to move, standing somewhat awkwardly in combat or when wielding their implements.

Heraldic beasts cannot have more than 10 HD. They split into two beasts if their family's influence would push them above such; the split need not be even. Few houses with more than one heraldic beast survive long before a schism.

HD 1 to 10    AC Breastplate    Bite Average
Move    As human    Int Cunning    Morale    Average

Heraldic Morale: Members of the family the beast embodies who can clearly see and hear it use its Morale or their own, whichever is greater.

The beast is normally fearless, only rolling its Morale when in beast duels.

Beast Duels

A common way to resolve disputes between nobles.

First a region for the contest must be agreed upon. This can take years if the nobles involved are more concerned with saving face than actually dealing each other harm. Disagreements over a duel's boundaries have been known to spark further duels, however.

The borders of the agreed region are clearly marked with flags bearing each nobles' colors and symbols. Each party is expected to contribute equally to the production of these flags, a fact which tends to prevent less-wealthy houses from competing with those with more capital or risk bankrupting themselves before the challenge begins.

Once the area has been marked by retainers, each house's heraldic beast is escorted to an opposing edge. The beasts understand the intent of this challenge, and will not willingly pass the flagged boundaries once engaged.

Within the boundaries, once a house's beast breaks from or submits in combat, the challenge is over. The family loses whatever stakes or honor were placed on the challenge, and will generally lose influence over the next few years, causing the beast to lose HD as well. A beast which defeats a higher HD beast is likely to earn status for its family and increase in HD accordingly.

Having one's heraldic beast kill another in such a contest is not unheard of but is considered distasteful in the same way as assassinations are.

Familiars

Several heraldic forms grant a beast the ability to cast find familiar. They can have as many familiars at a time as they can cast the spell in a day. The forms their familiars take are favored as pets and guardians by members of their families.

https://en.wikipedia.org/wiki/Coat_of_arms_of_Austria

Sample Heraldic Beasts

Heraldic beasts are traditionally given plural names which indicate ownership by their family.

The Bards of Shaelie

HD 9    AC Breastplate    Two Bites Average
Move    As human    Int Human    Morale    High

Owl: Only surprised 1-in-6
Crown: Increase Morale.
Ivy: Cast find familiar 1/day (it's a mass of vines and fruits).
Paws: Increase stealth.
Two-headed: Roll another head.
    Crow: Increase Int
Torch: Sheds light as a torch. Easier to see.
Arrows: Cast magic missile 2/day.

Familiar: A mossy sparrow.

The Gungutch Reapers

HD 2    AC Breastplate    Bite Average
Fly    As horse    Int Cunning    Morale    High

Lion: Increase Morale
Chained collar: Cast find familiar 1/day.
Spots: Increase stealth.
Hooves: Increase Move.
Winged: Grant a flying speed equal to its normal Move.
Farm implement: A slow but average-damage melee attack. Cast find familiar 1/day.
Fruit: Cast cure light wounds 2/day.

Familiars: A farm mouse. A farm cat.

The Nagas of Yenwidge

HD 4    AC Breastplate and Shield    Horns Average
Move or Swim    As human    Int Cunning    Morale    Average

Ram: Horn attack instead of bite.
Mane: Increase armor.
Stars: Sheds candlelight; cast magic missile 1/day.
Fins: Grant a swimming speed equal to its normal Move. Can hold its breath for an hour.
Long neck: Head attacks gain reach. Extra visible.
Spear or trident: An average-damage melee attack with reach.
Sword: An average-damage melee attack.

Penthilette's Bitter Herd

HD 5    AC Breastplate and Shield    Bite Heavy; Antlers Average
Move    As horse    Int Cunning    Morale    High

Boar: Increase bite damage.
Antlers: Increase or gain horn attack.
Wounds: Ignores lesser injuries (such as those which would deal less damage than its HD).
Hooves: Increase Move.
Dangerous tail: Stinger: An additional poison attack.
Shield: Add +shield to armor.
Flowers or herbs: Cast sleep 1/day. Cast protection 1/day.

Heraldic Forms

Any spells are cast as a caster level equal to the beast's HD.

The head reminds you of a (d12)

1. Lion: Increase Morale.
2. Fox: Increase Int.
3. Serpent: Poisonous bite.
4. Eagle: Only surprised 1-in-6.
5. Stag: Horn attack instead of bite.
6. Wolf: Increase bite damage.
7. Ram: Horn attack instead of bite.
8. Owl: Only surprised 1-in-6.
9. Crow: Increase Int.
10. Horse: Increase Move.
11. Dragon: Increase bite damage.
12. Boar: Increase bite damage.

The head is adorned with (d10)

1. Crown: Increase Morale.
2. Mane: Increase armor.
3. Chained collar: Cast find familiar 1/day.
4. Tusks: Increase bite damage.
5. Antlers: Increase or gain horn attack.
6. Flames: Attack also deals average fire damage.
7. Long tongue: Speak (but not understand) any language.
8. Beard: Increase Int.
9. Horns: Increase or gain horn attack.
10. Floating crown: Cast bless 1/day.

The beast is covered in (d8)

1. Lurid colors: Extra visible. Extra intimidating. Decrease stealth.
2. Spots: Increase stealth.
3. Scales: Increase armor.
4. Mist: Cast fog cloud 1/day.
5. Ivy: Cast find familiar 1/day (it's a mass of vines and fruits).
6. Wounds: Ignores lesser injuries (such as those which would deal less damage than its HD).
7. Stars: Sheds candlelight; cast magic missile 1/day.
8. Shell: Increase armor greatly; lower Move.

Its limbs tend towards (d6)

1. Claws: An additional average-damage claw attack.
2. Paws: Increase stealth.
3. Fins: Grant a swimming speed equal to its normal Move. Can hold its breath for an hour.
4. Talons: A fast but low-damage claw attack.
5. Hooves: Increase Move.
6. No forelimbs. Anything it wields floats. Roll again for hindlimbs.

Oh, and (d4)

1. Winged: Grant a flying speed equal to its normal Move.
2. Long neck: Head attacks gain reach. Extra visible.
3. Two-headed: Roll another head.
4. Dangerous tail: Roll another d4:
5. Stinger: An additional poison attack.
6. Another head (roll d12): It can bite and speak.
7. Spiked ball: An additional slow but heavy-damage attack.
8. Dazzling display: Cast charm person 1/day

Each heraldic beast wields two implements (d20 twice)

1. Sword: An average-damage melee attack.
2. Spear or trident: An average-damage melee attack with reach.
3. Axe or mace: A slow but heavy-damage melee attack.
4. Dagger or knife: A fast but light-damage melee attack.
5. Farm implement: A slow but average-damage melee attack. Cast find familiar 1/day.
6. Torch: Sheds light as a torch. Easier to see.
7. Shield: Add +shield to armor.
8. Arrows: Cast magic missile 2/day.
9. Harp: Cast charm person 2/day.
10. Orb: Cast light 2/day.
11. Bell: Cast alarm 2/day
12. Lightning: Cast light 1/day. Cast magic missile 1/day.
13. Banners: Cast find familiar 2/day.
14. Fruit: Cast cure light wounds 2/day.
15. Book: Cast detect magic 2/day.
16. Flowers or herbs: Cast sleep 1/day. Cast protection 1/day.
17. Shells: Cast silence 1/day.
18. Key: Cast knock 1/day.
19. Horn: Force a morale roll 1/day on all who hear. Enemies who fail break. Allies who had previous failed a morale roll rally.
20. Wheel: Re-roll a saving throw 1/day.

See also http://www.1km1kt.net/rpg/dragons-of-blood-and-water