Barkspawn (Level 5)

Keen Hearing and Smell. The mastiff has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Sidekick (Warrior):  Barkspawn is proficent in (Intimidation) checks and (Survival) 

The sidekick gains proficiency with all armour.

Hit Dice: 5d8

Improved Critical (Warrior):  The sidekick’s attack rolls score a critical hit on a roll of 19 or 20 on the d20.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 2) piercing damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be knocked prone.

Second Wind: The sidekick can use a bonus action on its turn to regain hit points equal to 1d10 + its level in this class. Once it uses this feature, it must finish a short or long rest before it can use it again. The sidekick can use this feature twice between rests starting at 20th level. (Warrior Sidekick)

Defender: The sidekick can use its reaction to impose disadvantage on the attack roll of a creature within 5 feet of it whose target isn’t the sidekick, provided the sidekick can see the attacker. (Warrior Sidekick)