Cold Aura. Any target that starts it's turn within 10 feet of the general takes 5 (2d4) cold dmg

Detect Life. The undead general can magically sense the presence of living targets up to 5 miles away. It knows the general direction they're in but not their exact locations.

Turn Immunity. The creature is immune to the effects that turn undead.

Undead Fortitude. If damage reduces the general to 0 hit points, it must make a Constitution saving throw with a DC of 5+ the damage taken, unless the damage is radiant or from a critical hit. On a success, the knight drops to 1 hit point instead.

Multiattack. The general makes two attacks with it's tyrant blade.

Tyrant Blade. Melee Weapon Attack: 1d20+10 to hit, reach 5 ft., one target. Hit: 20 (4d6 + 6) slashing damage. A creature damaged by this blade must succeed a DC 15 Constitution saving throw or be frightened by the undead general for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the blades effect for 24 hours. 

Dreadful Gaze. Choose a creature within 30 feet of the general. So long as the two of them can see each other, the general can force the target to make a Constitution saving throw, DC 18, so long as the creature isn't incapacitated. On a failed save, the target magically begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the target is petrified until freed by the greater restoration spell or other magic.

Opportunity Attack. HIT THEM.