Circle of Tailed Beasts

You become the vessel to a unique beast/monster.
You either have:
A 1-tailed sand-tanuki. A 2-tailed blue-fire cat. A 3-tailed dragon-turtle.
A 4-tailed volcano gorilla. A 5-tailed steam horse. A 6-tailed acid mollusk.
A 7-tailed armored beetle. An 8-tailed ox-octopus. Or a 9-tailed psychic kitsune.

Circle Spells

2nd-lvl Circle of Tailed Beasts feature

-1-Tail's Spells:                      -2-Tails' Spells:                       -3-Tails' Spells:
3rd Earthbind                          3rd Heat Metal                        3rd Mirror Image
5th Wall of Sand                     5th Fireball                               5th Wall of Water
7th Stone Shape                     7th Wall of Fire                        7th Control Water
9th Transmute Rock               9th Immolation                       9th Maelstrom

-4-Tails' Spells:                      -5-Tails' Spells:                        -6-Tails' Spells:
3rd Scorching Ray                 3rd Misty Steps                         3rd Acid Arrows
5th Ashardalon's Stride         5th Gaseous Form                   5th Stinking Cloud
7th Fire Shield                         7th Freedom of Movement    7th Vitriolic Sphere
9th Flame Strike                     9th Cloudkill                              9th Contagion

-7-Tails' Spells:                    -8-Tails' Spells:                         -9-Tails' Spells:
3rd Web                                 3rd Darkness                              3rd Mind Spike
5th Wind Wall                        5th Tidal Wave                          5th Clairvoyance
7th Storm Sphere                 7th Black Tentacles                  7th Locate Creature
9th Control of Wind              9th Bigby's Hand                      9th Mislead

Vicarious Behavior

3rd-lvl Circle of Tailed Beasts feature

Depending on the Tailed Beast you contain, tertiary traits will affect you.
-One-Tail: You cannot be interrupted when you go to sleep.
-Two-Tails: Like most felines, you have an upredictable mood.
-Three-Tails: You'd rather spend time underwater.
-Four-Tails: Fire/heat comforts you more so than it puts people on guard.
-Five-Tails: Running a lot is how you meditate.
-Six-Tails: You like really strong drinks and spicy foods.
-Seven-Tails: You can't stay too long inside, only outside there is a breeze.
-Eight-Tails: It is difficult to take something from you, you have a strong grip.
-Nine-Tails: You have a mischievous streak for pranks.

Unique Trait

6th-lvl Circle of Tailed Beasts feature

Through you, your Tailed Beast can manifest an exclusive talent they honed:
-One-Tail: You know the Mold Earth cantrip with sand you produce yourself.
-Two-Tails: Your flames become blue, you have advantage on fire damage.
-Three-Tails: You know the Water Breathing spell.
-Four-Tails: Your arms are covered in lava with the lvl 3 Burning Hands spell.
-Five-Tails: You know the Armor of Agathys spell, layered in scalding steam.
-Six-Tails: Your saliva becomes acidic with the Acid Aspersion cantrip.
-Seven-Tails: You can use your powder scale with the Dust Devil spell.
-Eight-Tails: Your saliva turns into sticky ink, it also paints liquids in opaque colors.
-Nine-Tails: You know the Detect Thoughts, gaining a psychic radar.

Rage Mode

10th-lvl Circle of Tailed Beasts feature

Available once per long rest, using all 2 Wild Shapes slots.
You are clad in arcane energy molded into the Tailed Beast's shape.
You take a quadrupedal posture as your silhouette is dark-red.
You sprout the tails of the beast and grow ears, claws, fangs, or wings, etc.

-Similar to the Barbarian's Rage, for 8 rounds you have:
.Advantage on Strength checks & saving throws.
.You cannot concentrate or cast spells.
.Resistance to non-magical bludgeoning, piercing & slashing damage.
.Your flying/swimming/walking speed is doubled.

-As your skin is pure energy, you have some bodily features:
.A tail swing does 1d4 slashing damage in a 6 ft/2 m reach.
.You can extend your arms like whips, grabbing in a 16 ft/5 m reach.
Your Claws deal 1d6 slashing damage.

Tailed Beast Mode

14th-lvl Circle of Tailed Beasts feature

Having learned the true name of the Tailed Beasts, you've solidified a true bond.
You can now freely access their real form at will while still being in charge.

.All transformations share the Huge size.
.You use 2 WS use and maintain it for only 18 min.

-SHUKAKU: You become a badger made of cursed sand. (Giant Badger)
In your reaction, you can shift your density to be resistant to bludgeoning, piercing and slashing damage.

-MATATABI: You become a cat with blue-flaming fur. (Sabertooth Tiger)
Your fur burns enemies on contact with 1d6 fire damage.

-ISOBU: You become a sea-strong kappa. (Dragon Turtle)
As a dash, you can roll into a ball and do 4d6 bludgeoning damage in your reach.

-SON GOKU: You become a bright-red gorilla. (Giant Ape)
Your Boulder Toss also deals fire damage.

-KOKUO: You become a dolphin-face white horse. (War Horse)
You are passively surrounded by 6 ft/2 m of white steam, advantage on DEX saves.

-SAIKEN: You become a jiggly poisonous slug. (Giant Slug)
You are immuned to acid, bludgeoning and poison damage.

-CHOMEI: You become a winged rhinoceros-beetle. (Carrion Beetle)
Flapping your insect wings pushes creatures smaller than you 6 ft/2 m back.

-GYUKI: You become a tentacled ox. (Giant Octopus)
In 1 action, you can whip 8d6 bludgeoning damage in a 12 ft/4 m reach.

-KURAMA: You become a mischievous kitsune. (Redtooth Werefox)
You are passively under the Detect Evil and Good spell.