Bleeding Construct

Immutable Form. The construct is immune to any spell or magical effect that would alter its form.

Fire Absorption. Whenever the construct is subjected to fire damage, it instead takes no damage and regains a number of hit points equal to half the damage dealt.

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

Magic Weapons. The construct's weapons are considered magical.

Molten Blood. This infernal construct is constantly oozing with searing hot blood. Whenever the construct takes slashing, piercing, or bludgeoning damage, all creatures within 5 feet of the construct take 18 (3d10) fire damage.

Multiattack. The construct makes three melee attacks: two with its spear, one with its Brand of Countless Sin.

Brand of Countless Sin. Melee Weapon Attack: +13 to hit, reach 10 ft., 1 target. Hit: 25 (3d10 + 7) [fire] damage. If the target is of an evil alignment, it must succeed in a DC 19 Wisdom saving throw or be frightened for 1 minute and take an additional 36 (6d10) fire damage.

Spear. Melee Weapon Attack: +13 to hit, reach 10 ft., 1 target. Hit: 20 (3d8+7) [piercing] damage.

Sanguineous Spew (Recharge 5-6). The construct spews out a torrent of molten blood from its mouth in a 15-foot cone. Each creature in the area must make a DC 19 Dexterity saving throw, taking 45 (10d8) fire damage on a failed save, or half as much on a successful one. 

Reveal True Nature. The construct reveals the melting corpse lying within its metal form. All creatures who can see the construct must make a DC 19 Wisdom saving throw. On a failure, the creature is frightened for 1 minute. On a success, the creature is immune to this effect for 24 hours. In addition, all creatures within 15 feet of the construct must make a DC 19 Dexterity saving throw, taking 30 (5d10) fire damage on a failed save or half as much on a success as blood spews from the construct's form.

Legendary Resistance (3/day). If the construct fails a saving throw, it can instead choose to succeed.

The construct can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The creature regains spent legendary actions at the start of its turn.

Brand of Countless Sin. The construct makes one attack with its Brand of Countless Sin. 

Endless Hatred. The construct moves up to its movement speed towards one creature of its choice.

Sanguineous Spew (Costs 2 Actions, Recharge 5-6). If available, the construct uses its Sanguineous Spew action.