Multiattack

The wyvern knight makes two lance attacks. If the wyvern knight is riding a war wyvern, its mount can then make one bite, claw, or stinger attack.

Lance

Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 9 (1d12 + 3) piercing damage plus 10 (3d6) poison damage. The wyvern knight has disadvantage on attacks with this weapon against creatures within 5 feet of it and can wield this weapon in one hand instead of two while mounted.

Heavy Crossbow

Ranged Weapon Attack: +3 to hit, range 100/400 ft., one target. Hit: 5 (1d10) piercing damage plus 10 (3d6) poison damage.

Dagger

Melee or Ranged Weapon Attack: +6 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 5 (1d4 + 3) piercing damage plus 10 (3d6) poison damage.