Might of the Master. The following numbers increase by 1 when your proficiency bonus increases by 1: the iron defender’s skill bonuses, the bonuses to hit and damage of its bite, and the number of hit points restored by its Repair action.

Vigilant. The iron defender can’t be surprised.

Mechanical Hunter. In combat, the mechanical hunte 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, or Help action.

If the mending spell is cast on it, it regains 2d6 hit points. If it has died within the last hour, you can use your smith’s tools as an action to revive it, provided you are within 5 feet of it and you expend a spell slot of 1st level or higher. The iron defender returns to life after 1 minute with all its hit points restored.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target you can see. Hit: 1d4+3 piercing damage. The Creature must make a DC 9 + 2 Dexterity saving throw otherwise the Mechanical Hunter grapples onto the target.
The target's movement speed is halved and the mechanical hunter stays within 5 ft if the target moves. It can repeat the saving throw at the end of each of its turn

Powder Core. This creature explodes setting its hp to 0 dealing 2d8 fire damage to every creature within a 20 ft radius. If this creature drops to 0 hp the Artificer can use his reaction to instantly trigger this action. It can’t be restored revived if it uses this action.

Distracting Pounce. The Mechanical Hunter can give advantage if you make a ranged attack against a target in 5 ft range of the Mechanical Hunter