BITTER DRYADS (Brothers/Children of the Pines from the Chronicles of Corum)

The People of the Pines/ Rodney Matthews/ 1977

AC +4 (see below)    HD 4+4 (see below)     Move 100% Normal Human     ML 10 (see below)

Once mortals, the Fomorians poisoned the first with mistleberries and transfused them with the sap of winter pines, making them undead. The Dryads now carry out the ritual themselves, sometimes even persuading the living to join them of their own will - but otherwise by submission.

Bitter Dryads retain their mortal form but skin and hair turns green. Morphic resonance has evergreen leaves and needles, moss, lichens and berry-like growths replace their hair, clothing and personal ornament over time. They bleed green, sticky and slow.

They prefer the shade of the forest, the gloom of winter, and the dark of night, but are not vulnerable to sunlight.

Retaining their intelligence and memories, the Bitter Dryads are the ironic, rustling voice of the  Fomorians in the mortal sphere. They are fully conscious of what they do even as it goes against anything they once loved or believed in their mortal life.

Three blasts of the Horn will strike them as instantly dead as it does the Half-Dead.

The Dryads are inextricably linked (and loyal) to the Fomorians through their weird reptilian steeds.

Dryad Horses are intelligent, capable of subvocal/telepathic communication with their rider and the Fomorians, and serve to direct the Dryads according to that greater will.

It is said that these lizard-things are vomited up by the Fomorians, fully formed extensions of their dire personality.

• As long as a Dryad is in the presence of their Horse, they are an AC +4 HD 4+4 Invulnerable Monster. If they are mounted, they regenerate 1 hp/round - even from 0 hp - and cannot be Turned. 
• Treat mount and rider as a single unit/statblock wherever possible/reasonable.
• A Dryad without a Horse is AC +2 HD 2+2 and normally vulnerable; they also have a -1 Initiative penalty. Morale drops to 8 (or 6 vs. fire). Turned as similar HD undead.
• A Horse without a Dryad is AC +4 HD 2+2, an Invulnerable Monster and regenerates 1 hp/round. Move without a rider is 200% Normal Human, 150% with an unarmoured or shielded rider, 100% with an armoured rider. It is otherwise mechanically the same as a Bitter Dryad.
• No armour benefit unless it is better than their base AC. Shield bonus stacks.
• Can make weapon, missile and unarmed attacks with a Strength of 13 and a Dexterity of 10.
• Immune to cold, gas, hold, charm, sleep and missiles (inc. magic missile).
• Save vs. fire at -2 and take +1 damage per die (ML 8 vs. fire).
• Surprise 1-3 on d6 and undetectable when stationary 1-4 on d6 in evergreen/winter forest.
• At 0 hp, unless by fire or acid, the Dryad is helpless, not killed, and able only to sense and speak. Even beheading and dismembering cannot silence them.
• Dryad Horses try to recover their fallen riders.
• Killing a Dryad's Horse allows the Dryad to be killed with normal damage.

Commentary.

I first encountered the Brothers of the Pine in The Best of White Dwarf Scenarios Vol. II. 

I hadn't read the Chronicles of Corum at this stage, so they were just a cool monster in their own right. 

I remember being fazed by the '-20% Morale' because I thought Morale was on 2d6 not d%, but assumed it was the kind of shorthand that I'd eventually get to understand. At that stage, I thought of rpgs (and rpgs being mainly D&D) in general being a new thing, rather than something that had been around for 10+ years, and expected there to be a lot more compatibility between them than there was.

I've used the BECMI/OSE Wood Golem as the base monster for both mount and rider. 

The relationship of the Pine People to their mounts was something I'd forgotten about, and I couldn't not include it.