Clockwork Centurion

Magic Resistance. The clockwork has advantage on saving throws against spells and other magical effects.

Unusual Nature. The clockwork doesn’t require air, food, drink, or sleep.

Glass casing. All the Centurions are encased in magical glass that shines like oil in water, but its still fragile giving them Vulnerability to bludgeoning damage.

Mysterious Ticking. When the clockwork is not resting it constantly gives off a ticking sound like a clock, giving it Disadvantage on stealth checks.

Suspended Animation.  The Clockwork Centurion can attach itself to a winding station and remain in a state of sleep for an infinite amount of time until something releases it from the winding station

Fanatical Mission. The Clockwork Centurion has a one track mind, to complete the mission it was given by its creators in the most efficient means possible. 

Multi-attack. The Clockwork Centurion makes 2 attacks, one Arm Blade Slash and one Crossbow Shot, Witch Bolt spell, or Reconfigure ability

Arm Blade Slash. A retractable blade that self sharpens as it deploys from the compartment on the Centurions right arm

Weapon Attack: +6 to hit, reach 5 ft., one target.  1D6+6 slashing damage

Crossbow shot. The fires a concealed Crossbow from its left arm

Weapon Attack: +8 to hit, reach 80 ft., one target. 1D8+2 piercing damage

Spellcasting. The Centurion can cast Witch Bolt 3/day

Reconfigure. The Clockwork Centurion Rotates and twists its limbs in an inhuman fashion in order to move an additional 5 feet of movement in any direction to an unoccupied space