Arsen, Nemean Champion

Pounce. If Arsen moves at least 20 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 18 Strength saving throw or be knocked prone. If the target is prone, Arsen can make one bite attack against it as a bonus action.

Indomitable (2/Day). Arsen rerolls a failed saving throw.

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

Impenetrable Hide. Arsen is immune to bludgeoning, piercing, and slashing damage from non-magical attacks.

Lethal Weapons. Arsen's claw and bite attacks are magical. If a creature is reduced to 0 hit points by one of these attacks, that creature dies. 

Multiattack. Arsen can make two attacks wither its bite or claw.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 17 (2d10 + 6) piercing damage.

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 6) slashing damage.

Daunting Roar. Each creature of Arsen's choice that is within 60 feet of the dragon and aware of it must succeed on a DC 16 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.

Arsen can take 2 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. Arsen regains spent legendary actions at the start of his turn.

Attack. Arsen makes an attack using his bite or claw. 

Teleport (Costs 2 actions). Arsen, along with anything or anyone he is carrying,  magically teleports up to 60 feet to a point he can see within range.