Hollow Knight on a Mawhound (Art by Dan Smith)

A feared wasteland rider spoken of only in whispers around dying campfires. 
Hollow Knights are silent warlords encased in rune-scarred armor. No face has ever been seen beneath the helm.

 Init: +2
Attack: Rune-forged cleaver +5 melee (1d10+2) or hooked chain-lance +4 ranged (1d8 and pull target 10’)
AC: 18            HD: 5d10        MV: 25’ or mounted 50’        Act: 1d20
Special Powers: Mounted Charge, Fear Aura, Impossible Endurance, Soul-Bound Armor
SV: Fort +5, Ref +3, Will +4             Alignment: Chaotic

If the Hollow Knight charges while mounted on the Mawhound, both attack in the same round:

Any 0-level character or creature of 1 HD encountering the Hollow Knight must make a DC 13 Will save or immediately flee for 1d4 rounds.

The Hollow Knight ignores the first critical hit suffered each combat. The blow lands, but the knight barely reacts.

If reduced to 0 HP, the armor collapses empty… unless the Mawhound still lives. One round later, black vapor reforms the knight beside the beast with 1d8 HP restored.

Critical Die: 1d10 (table III)

Fumble: A Hollow Knight never fumbles.  The Knight can miss just not critically miss.

 

Init: +3
Attack: Bite +6 melee (1d12) and gore-horn +4 melee (1d8)
AC: 16            HD: 6d8          MV: 50’          Act: 1d20+1d14
Special Powers: Frenzied Bite, Trample, Scent the Living, Rider Bond
SV: Fort +6, Ref +4, Will +2       Alignment: Neutral

If the Mawhound hits with its bite, it may immediately make a free gore-horn attack.

Creatures smaller than man-sized struck during movement must succeed on a DC 15 Reflex save or take 1d6 damage and fall prone.

The Mawhound can smell blood, fear, and warm flesh up to 300 feet away even through darkness or fog.

While ridden by the Hollow Knight:

Critical Die: 1d12 (table IV)

The Mawhound prefers to cripple prey first, circling and tearing at fallen victims before delivering a killing bite.

 

The Hollow Knight blocks passage through a dead canyon, demanding a living sacrifice, treasured memory, or a duel beneath the black moon. 

The Mawhound is found wandering riderless across the wastes. At night, the Hollow Knight reforms beside it.

The pair pursue escaped prisoners through ruined lands, offering the PCs coin or survival in exchange for assistance.

Magical Weapon: Rune-Cleaver 

Weapon Type: Two-handed sword/cleaver
Damage: 1d10+2 melee (counts as a +2 magical weapon)

Once per day, upon slaying a foe, the wielder may immediately make another melee attack against a nearby target. Each use permanently stains the wielder’s dreams with visions of the Black Wastes. After 7 uses this way, the Judge may require corruption checks.