Pack Tactics. The serjeant has advantage on an attack roll against a creature if at least one of its allies is within 5 feet of the creature and the ally isn't incapacitated.

Multiattack. The Serjeant makes two melee weapon attacks.

Arming Sword. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit:  7 (1d8 + 3) slashing damage.

Heavy Crossbow. Ranged Weapon Attack: +3 to hit, range 100/400 ft., one target. Hit: 5 (1d10) piercing damage.

Leadership (Recharges after a Short or Long Rest). For 1 minute, the knight can utter a special command or warning whenever a nonhostile creature that it can see within 30 feet of it makes an attack roll or a saving throw. The creature can add a d4 to its roll provided it can hear and understand the knight. A creature can benefit from only one Leadership die at a time. This effect ends if the knight is incapacitated.

Parry. The serjeant adds its 2 to its AC against one melee attack that would hit it . To do so, the serjeant must see the attacker and be wielding a melee weapon.