Owlbear Bond

Some rangers do not simply watch over the wilds, they raise its fiercest children as kin. Rangers of the Owlbear Bond form a mystical pact with an owlbear cub, nurturing it from a wide-eyed fledgling into a mighty guardian. Bound by primal magic and deep trust, ranger and owlbear fight side by side, each protecting the other through countless battles. As the bond grows stronger, the owlbear becomes a loyal mount, an independent hunter, and a living embodiment of untamed fury, roaring in defiance of any who would threaten its companion.

Guardian Cub

You magically bond with an owlbear cub, which fights at your side. The cub acts immediately after your turn and obeys your commands. You must use a bonus action to command it to take the Attack, Dash, Disengage, or Help action; otherwise, it only takes the Dodge action. If the cub drops to 0 hit points, it disappears and reappears 8 hours later at full health. Its hit points, attacks, and saving throws scale with your ranger level and proficiency bonus.

Wildgrown Guardian

At 7th level, your cub matures into a fully grown owlbear — a powerful ally and fearsome mount.
Your owlbear companion grows to a Large size and can serve as a mount if you are Small or Medium. Its base movement speed increases by 10 feet. It Also gains multiattack and a Major stat increase (See stat block)
Additionally, your owlbear gains the Hardened Hide trait: when it is hit by an attack, it can use its reaction to reinforce its feathers and muscles, adding +2 to its AC for that attack, potentially causing it to miss.

Kindred Spirits

At 11th level, your bond with your owlbear becomes seamless and instinctive.
Your owlbear companion now acts independently in combat. It rolls its own initiative and no longer requires your bonus action to command it. It will defend you and follow your spoken instructions to the best of its ability.
In addition, you and your owlbear share a primal telepathic link. You can communicate simple thoughts, emotions, and commands telepathically with your owlbear while you are within 1 mile of each other.

Primal Fury

At 15th level, your owlbear can unleash the full force of its wild blood.
As a bonus action, your owlbear can enter a primal rage for 1 minute. While raging, it gains the following benefits:

• It has resistance to all damage except psychic damage.

• It deals additional damage equal to your proficiency bonus on all melee weapon attacks.

• It has advantage on Strength checks and Strength saving throws.
  
  Your owlbear can enter this rage a number of times equal to half your proficiency bonus (rounded down). All expended uses are regained when you finish a long rest.