Warhorse Skeleton

A warhorse skeleton on the party's side is the necromancer PC's mount, a relic the death cleric raised from a battlefield ossuary, or the gift of an evil patron the party has not yet decided to sever. It is Lawful Evil and unintelligent, so it does not refuse orders, but it does not improvise either. Treat it like a fast cart with a kick.

The pull is the 60 ft. walk speed and the charge mechanic. With Hooves at +6 for 7 average bludgeoning, plus the rule that a 20+ ft. straight charge knocks Large or smaller creatures Prone, the warhorse skeleton is built to deliver a paladin or fighter into the back rank of an enemy formation in one round. The mounted PC gets there fast, the skeleton drops the lead enemy prone with the charge, and the rider gets the round-two follow-up against an enemy who has to spend half their movement standing up. That two-turn opener is worth more than the skeleton's middling damage.

The cost is bookkeeping and atmosphere. The party riding a skeletal horse will be turned away from inns, refused at city gates, and detected by paladins. Carry a tarp. Beyond the social cost, the skeleton is fragile: 22 HP, AC 13, and vulnerability to Bludgeoning means a single ogre's club can end it in one hit. Don't ride it into a fight where the lead enemy swings a maul.

The undead detail worth using: it does not breathe, eat, sleep, or tire. The party can ride through the night to make a deadline they shouldn't have made, and the GM can use that capability for one specific plot moment per arc. Just don't let the skeleton become a transit puzzle every session.

A warhorse skeleton is a lich's outrider, a death knight's mount, or a battlefield revenant still riding the same patrol it died on. Run it as a charging mount with Lawful Evil intent, not a roaming undead beast, because the speed and the prone-on-charge mechanic only matter if it has space to run and a target it wants to hit.

Open with the charge. 60 ft. walk speed and a 20 ft. straight-line requirement means the skeleton picks a target across the room, runs at them, and lands Hooves at +6 for 7 average bludgeoning plus Prone on a Large or smaller creature. That's a soft hit but a real condition, and a prone PC eats the next round of enemy attacks at advantage. If the skeleton is paired with a rider, an archer formation, or a second wave of enemies, the prone PC is the priority target for everyone else. Run two warhorse skeletons together and the party loses two front-rankers to the floor in round one.

Target priority is whichever PC is alone or out in front. The skeleton is mindless about morality but pattern-driven about pursuit. Once it has picked a target it stays on that target, charging out to 60 ft. to set up the next 20 ft. line, until the target is dead or the skeleton is. Vulnerability to Bludgeoning is the party's escape valve: a clerical mace or barbarian's hammer hits 22 HP and AC 13 hard, and the skeleton drops in one round of focused melee.

It does not retreat. It does not flee. It charges, prones, kicks, and dies on the floor. The encounter ends when one of those things stops being possible.

Have it run on broken hooves, sparking against the stones. The sound is the warning. The party should hear it coming a round before they see it.