Weapon Master. The Aberrant Blade Knight has proficiency with all weapons, though they prefer to use maces, shortswords, great swords, crossbows, and spears. 

Spellcasting. The Aberrant Blade Knight is a 3-level spellcaster. Its spellcasting ability is intelligence (spell save DC 18, +3 to hit with spell attacks). Any radiant damage the Aberrant Blade Knight deals is replaced with force damage. The Aberrant Blade Knight has following Paladin spells prepared:  
1st level (4 slots): Wrath Smite, Thunderous Smite, Searing Smite, Shield of faith, Command
2nd level (3 slots): Magic Weapon, Branding Smite, Lesser Restoration, Aid
3rd level (2 slots): Crusader’s Mantle, Blinding Smite, Aura of Vitality

Disarm. The Aberrant Blade Knight flings the weapon of a monster it is locked in combat with, at least within 5 ft of it.

Multiattack. The Aberrant Blade Knight can make one attack with its equipped weapon (not spear) and one with its spear or shield, or two with its crossbow.

Weapon strike. Melee Weapon Attack: +2 to hit, reach 5 ft., 1 target. Hit: 2d10 + 5 slashing, piercing, or bludgeoning (depending on the weapon they have equipped minus the spear) damage. 

Spear Jab. Melee Weapon Attack: +2 to hit, reach 10 ft., 1 target. Hit: 1d10 + 5 piercing damage. 

Shield Bash. Melee Weapon Attack: +2 to hit, reach 5 ft., # target. Hit: 1d12 + 5 bludgeoning damage, 1d8 piercing damage, and the target must succeed a DC 14 constitution save, or become stunned.

Crossbow. RangedWeapon Attack: +# to hit, range 10/830 ft., 1 target. Hit:  2d8 + 5 piercing damage.

Parrying Strike. The Aberrant Blade Knight makes an attack with its weapon (not spear) towards a creature within 5 ft of it that hits an attack against it.