Ichabarr

Ichabarr is the headless stallion-lord of the Herd of the Damned, a herd of skeletal centaurs that roams the Parchwood Timberlands of northern Tal'Dorei, in the adventure hook Legend of the Headless Horse-Man from Tal'Dorei Campaign Setting, set in 812 PD. Twenty four years later, in the adventure hook Headless Horse-Man, set in 836 PD, Ichabarr and the herd still marauding the region, spiriting away young bachelors.

Description
Ichabarr is headless carrying his flaming head in his arm.

Tal'Dorei Campaign Setting suggests to use a modified centaur statblock for Ichabarr, which nearly doubles his average hit points and gives him certain damage resistances and extra necrotic damage to weapon attacks. He is also given the nightmare's Ethereal Stride ability.

Tal'Dorei Campaign Reborn suggests slightly less modified version of centaur statblock, also notes on immunities and vulnarabilities specific to skeleton creatures and adds an optinal abilities for skeletal centaurs: Spirit Away. The centaur skeleton and up to three creatures within 5 feet of it can magically enter the Ethereal Plane from the Material Plane, or vice versa. An unwilling creature that succeeds on a DC 13 Charisma saving throw can resist this effect.