Rangers have a connection to the nature spirits that inhabit the wild, untamed lands they roam. The Beast Soul is especially attuned to bestial spirits, and taps into the raw power of an ancient spirit beast.

Level 3: Spirit Beast Companion

At the 3rd level, you form an unbreakable bond with a fey spirit, grating you the ability to summon it as a Spirit Beast. When summoned, the spirit can take the form of any beast that is no larger than medium and has a challenge rating (CR) of 1/2 or lower. The beast is Friendly to you and your allies and obeys your commands. 

Abilities and Stats. Add your proficiency bonus to the beast’s AC, DC, attack rolls, damage rolls, all skill checks, and all saving throws. The beast keeps all abilities except Multiattack, and makes Intimidation skill checks with Strength or Dexterity instead of Charisma. The beast has hit points equal to 5x your character level +5. It also has a number of d8 hit dice equal to your character level and can use them during a short rest to regain hit points.

In Combat. In combat, the beast acts during your turn and can move and take reactions on its own. You must use a Bonus Action to command it to attack, or you can sacrifice one of your attacks when you take the Attack action to command the beast. If you have the Incapacitated condition, the beast acts on its own.

Spell Share. When you cast a spell targeting yourself, you can also affect your Spirit Beast companion with the spell if it’s within 30 ft. of you. In addition, when the spirit beast hits a creature under the effect of your Hunter’s Mark spell, the beast deals extra Force damage equal to the bonus damage of that spell.

Restoring or Replacing the Beast. When your beast's physical form is killed, its spirit returns to the Feywilds. Your spirit beast can be summoned as a ritual once per day for free, and can be resummoned or changed additional times by expending a spell slot. The ritual takes 1-minute of concentration and summons the spirit beast with full health in whatever form you choose (that meets the above requirements). 

Level 7: Exceptional Training

When you take a Bonus Action to command your Spirit Beast Companion beast to take an action, you can also command it to take the Dash, Disengage, Dodge, or Help action using its Bonus Action.

In addition, whenever it hits with an attack roll and deals damage, it can deal your choice of Force damage or its normal damage type.

Level 11: Greater Spirit Beast

At the 11th level, your Spirit Beast Companion can now take the form of any beast that is Large or smaller and has a challenge rating of 2 or lower. The Greater Spirit Beast keeps all aspects of the Spirit Beast Companion, except it can now use Multiattack (if it has it), the hit die increases to a d10, and it now has hit points equal to 6x your character level +10.

Level 15: Foe Breaker

At the 15th level, your Hunter's Mark spell no longer requires concentration or a target. Instead, choose a creature or humanoid species to mark as your prey. You and your beast gain the benefits of Hunter's Mark against all creatures or humanoids of that type until it is changed using your bonus action, or the spell ends.

In addition, you and your beast have advantage on all Strength and Dexterity skill checks and saving throws against any creature affected by Hunter's Mark.