Black-Eye Knight

Aggressive. The black-eye knight can use its bonus action to move up to its speed towards an opponent it can see.

Chill of the Boreal Valley. The black-eye knight deals an additional 4 (1d8) cold damage with its longsword attacks (included in the attack description). Creatures that take cold damage from the black-eye knight must also succeed on a DC 13 Constitution saving throw or take a cumulative 10-foot penalty to their movement until the end of their next turn.

Multiattack. The black-eye knight makes two longsword attacks.

Longsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) slashing damage plus 4 (1d8) cold damage, or 8 (1d10 + 3) slashing damage plus 4 (1d8) cold damage if used with two hands. A creature hit by this attack must also succeed on a DC 13 Constitution saving throw or have its speed reduced by 10 feet until the end of its next turn.

Cold Breath (Recharges 5-6). The black-eye knight exhales a blast of frigid air in a 15-foot cone. Any creature caught in the area must make a DC 13 Constitution saving throw, taking 18 (4d8) cold damage on a failed save, or half as much damage on a successful one. A creature that fails its save also has its speed reduced by 10 feet until the end of its next turn.