Bernard

Amphibious. The Bernard can breathe air and water.

Status Master. The Bernard is immune to all status conditions. 

Multiattack. The Bernard makes three attacks: one with its bite and two with its claws.

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

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Breath Weapons (Recharge 5–6). The Bernard uses one of the following breath weapons.

Fire Breath. The Bernard exhales fire in a 30-foot cone. Each creature in that area must make a DC 17 Dexterity saving throw, taking 55 (10d10) fire damage on a failed save, or half as much damage on a successful one.

Weakening Breath. The Bernard exhales gas in a 30-foot cone. Each creature in that area must succeed on a DC 17 Strength saving throw or have disadvantage on Strength-based attack rolls, Strength checks, and Strength saving throws 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.

Paralyze Evil. The Bernard radiates yellow light in a 30-foot sphere. Each Evil Aligned creature in that area must succeed on a DC 18 Dexterity saving throw or become temporarily paralyzed 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. 

The Bernard 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 Bernard regains spent legendary actions at the start of its turns.

Legendary Bond.  If the Bernard finds a player that it sees fit, the Bernard can choose to form a Legendary Bond with said player. The Bernard takes on physical characteristics that resemble the Player, and gains the ability to use Bond Teleport, Bond Absorption, and Bond Attack.

Bond Teleport.  A Bernard can choose to teleport to its bonded player, given that there is enough space for the Bernard to do so, The Bernard can also teleport its bonded player to it, given that the player is willing. 

Bond Absorption.  When the Bernard is within a 50ft radius of its bonded player, the Bernard can absorb damage dealt to its bonded player.

Bond Attack. When the Bernard is within a 10ft radius of its bonded player, the Bernard adds +3 to attack and damage rolls that the player makes, and the player adds +3 to all attack and damage rolls that the Bernard makes. 

Mythical Bond.  If the Bernard has been bonded to its player for more than a year, then the bond between the player and the Bernard increases, allowing the Bernard to use Bond Sacrifice.

Bond Sacrifice.  If the Bernard's bonded player dies, the Bernard can give up its life force to return the bonded player back to life. This resurrection works 100% of the time, and returns the player back to life with no issues. As a result of this action, the Bernard is reduced to 0 hit points, and must make a DC 25 Constitution Saving Throw, or instantly be turned into glowing ash.