Arcane Guardian

Inerrant Traits:

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).

Vigilant. The defender can’t be surprised.

Steel Defender lineage. In combat, a steel defender shares your initiative count, but it takes its turn immediately after yours. With your Arcane Guardian, you choose if they take their turn before or after you. The Guardian can move and use its reaction on its own, 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.

If the mending spell is cast on it, it regains 3d6 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 steel defender returns to life after 1 minute with all its hit points restored.

Keen Senses. The defender has advantage on Wisdom checks.

Telepathic Bond. While the defender is on the same plane of existence as its master, it can magically convey what it senses to its master, and the two can communicate telepathically.

Given Traits: 

The Arcane Guardian- Walrus takes (1)  Action

Tusk Attack: Your guardian rocks itself back onto its tail, protruding its tusks forward. It strikes down with its tusks, slamming its body onto the ground. The ground quakes beneath it. Melee Weapon Attack: +6 to hit, reach 15ft., one target you can see. Hit: 2d12  piercing damage. Each creature in a 30ft radius must make a dexterity saving throw DC15 or take 4d4 force damage

Bellowing Blubber: Releasing the excess air built up in its gear and valves, it emits a low resonance from the slats between its metal plates. Range: 60ft. A creature in range of the sound must make a DC15 wisdom save or take 3d6 physic damage. On a successful save a creature takes half damage. 

Excavating Ivory: While stationary your Arcane Guardian can use its action to release its jaw sinking it tusks into to ground. It can now burrow at a speed of 60ft leaving a 10ft diameter tunnel

Inerrant Traits:

Repair (3/Day). The magical mechanisms inside the defender restore 2d8 + 2 hit points to itself or to one construct or object within 5 feet of it.

Deflect Attack. The defender imposes disadvantage on the attack roll of one creature it can see that is within 5 feet of it, provided the attack roll is against a creature other than the defender.

Whenever your steel defender uses its Deflect Attack, the attacker takes force damage equal to 2d12 + your Intelligence modifier.

When all 4 Arcane Guardians come together (Elephant- Air, Bear- Earth, Unicorn- Fire, Walrus-Water, ), they seamlessly form a massive humanoid construct towering 60ft high. The new Construct has enhanced actions and abilities than its previous forms.

Elephant- The powerful force behind the mechanical elephant's stampede action is now imbued into the construct. Using an action to charge an opponent, you create an Earthquake. The elephants 7ft Tusks now sever as curved blades dealing 2d12 slashing damage each. 

Bear- The keen senses of the bear allow the new Construct to be aware of it surroundings and be ready for attach. [feat]Sentinel[/feat] as well as advantage on  wisdom saves and checks.

Unicorn- The Unicorn's adamantine horn now serves as tuning rod for magical energy. Drawing in properties from the thread of magic itself, the construct can now cast Prismatic Spray. As a bonus action the Construct can use the Unicorn's horn to ram a target with in 30ft of it. Dealing 3d6 piercing damage. 

Walrus- The Cold Iron, 4ft tusks of the walrus, now serve as daggers dealing 3d6 slashing damage each. Range: 30ft reach/ 120ft thrown. They can also be used to to burrow, creating a 90ft tunnel with a burrow speed of 200 ft per round

Construct adds Earth, Air, Fire, and Water to its damage immunities.