Might of the Master. The following numbers increase by 1 when your proficiency bonus increases by 1: the defender’s skill and saving throw bonuses (above), the bonuses to hit and damage of its rend attack, and the number of hit points restored by its Repair action (below).

Void Sight. The construct can see through magical darkness up to 60ft

Undead Construct. In combat, the undead construct shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take one of the actions in its stat block or the Dash, Disengage, Help, Hide, or Search action.

You can spend 1-minute summoning necrotic energies and heal the construct 2d6 hit points. If it has died within the last hour, you can use your essence as an action to revive it, provided you are within 5 feet of it and you expend a Warlock spell slot. The construct returns to life after 1 minute with all its hit points restored.

At the end of a long rest, you can create a new body for your construct's essence. If you already have an undead construct from this feature, the first one immediately perishes.

Fury of the master.  Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target you can see. Hit:1d8 + PB force damage.

Devour. When the construct reduces a creature to 0 hit points with its melee attack on its turn, the construct can take a bonus action to devour the creature regaining 2d4.

Devour's Dice count increases by 1 when your PB increases by one.

Wails of the Dead (1/short rest).  When an ally creature within 30 feet of the construct that it can see hits with a melee attack, the construct begins to let out wails of the dead adding an additional 1d6 of Psychic Damage to the ally's attack.