Cosmo

Adamantine Plating. Any critical hit against Cosmo becomes a normal hit.

Deadly Critical. Cosmo scores a critical hit on a roll of 18 ,19 or 20 and rolls the damage dice three times, instead of twice.

Magic Resistance. Cosmo has advantage on saving throws against spells and other magical effects.

Magic Weapons. Cosmo weapon attacks are magical.

Warforged Resilience. Cosmo has advantage on saving throws against being poisoned and is immune to disease. Magic can’t put it to sleep.

Sure-Footed. Cosmo has advantage on Strength and Dexterity saving throws made against effects that would knock it prone.

Whirlwind of Weapons. A magical aura of weapons surrounds Cosmo in a 10 foot radius. At the start of each of his turns, any other creature in the aura takes 14 (4d6) force damage.

Multiattack. Cosmo makes three axehand attacks and once with thunder strike 

Axehand. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 19 (5d8 + 6) slashing damage, plus 11 (5d10) slashing damage if the target is prone.If the target is a creature other than an undead or a construct, it must succeed on a DC 12 Constitution saving throw or lose 5 (1d10) hit points at the start of each of its turns due to an infernal wound. Each time Cosmo hits  the wounded target with this attack, the damage dealt by the wound increases by 5 (1d10). Any creature can take an action to stanch the wound with a successful DC 12 Wisdom (Medicine) check. The wound also closes if the target receives magical healing.

Flying dagger of Shadow. Ranged Spell Attack: +12 to hit, range 120 ft., one target. Hit: 10 (1d6 + 7) necrotic damage, and if the target is a creature, it must succeed on a DC 20 Constitution saving throw or be poisoned until the end of its next turn.

Sweeping Axe (5/day). Cosmo makes a sweep with its axehand, and each creature within 10 feet of it must make a DC 17 Dexterity saving throw. A creature takes 19 (8d8 + 6) slashing damage on a failed save, or half as much damage on a successful one.

Thunder Strike. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 15 (4d10 + 4) thunder damage, and if the target is a creature, it must succeed on a DC 17 Constitution saving throw or be deafened and stunned until the start of Cosmo next turn.

Rotting Fist (3/Turn). Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 14 (3d6 + 4) bludgeoning damage plus 21 (6d6) necrotic damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or be cursed with mummy rot. The cursed target can’t regain hit points, and its hit point maximum decreases by 10 (3d6) for every 24 hours that elapse. If the curse reduces the target’s hit point maximum to 0, the target dies, and its body turns to dust. The curse lasts until removed by the remove curse spell or other magic.

Martial Prowess (3/Turn). When Cosmo hits a creature with a melee weapon attack, the attack deals an extra 11 (2d10) damage of the weapon’s type, and the creature must make a DC 15 Strength saving throw. On a failure, Cosmo can push the creature up to 10 feet away from it, knock the creature prone, or make the creature drop one item it is holding of Cosmo choice.

Teleport. As a bonus action, Cosmo can teleport up to 30 feet to an unoccupied space it can see.

Parry. Cosmo adds 7 to its AC against one melee attack that would hit it. To do so, Cosmo must see the attacker and be wielding a melee weapon.

Deflect Missile. In response to being hit by a ranged weapon attack, Cosmo deflects the missile. The damage he takes from the attack is reduced by 2d10 + 12. If the damage is reduced to 0, Cosmo catches the missile if it’s small enough to hold in one hand and Cosmo has a hand free.