Wrath Incarnate

Amphibious. The dragon can breathe air and water.

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

Wrath Incarnate. You summon an avatar of Wrath. Only summon-able if you have contracted with/worship the sin of wrath (Summons as an action), or at DMs discretion in times of great anger (Summons as a free action here).

Enrages Owner. Character that summoned Wrath must attack nearest creature every turn when possible while Wrath is summoned, but Wrath can prevent you from attacking allies by directing your wrath (This is a charm effect where if you don't have an inherent  resistance/advantage you auto fail the check, If you have an inherent resistance/advantage Roll Once against a dc 15 resist charm check, and an immunity becomes Roll Twice against a DC 15 resist charm check and take the higher value).

Rage God. Auto succeeds Strength checks and saves as well as intimidation checks while enraged. Auto fail Intelligence checks and saves while enraged.

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage plus 9 (2d8) acid damage.

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.

Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Acid Breath (Recharge 5–6). The dragon exhales acid in a 90-foot line that is 10 feet wide. Each creature in that line must make a DC 22 Dexterity saving throw, taking 67 (15d8) acid damage on a failed save, or half as much damage on a successful one.

The dragon 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 dragon regains spent legendary actions at the start of its turn.

Detect. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 23 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.