Clara's weapon and pet

Name: Pounce
Species: doom kitten
Type: Combat Pet
Description: Looks like a normal cat with black fur and white paws and chest, but if someone looks closely they can see darker black stripes on the cat's head. Is usually lazy but can sense danger and knows when he has to help in battle.
Abilities:

Name: Night claw
Description: Pounce's claws will change color from white to black. Pounce will leap at the enemy and slash his claws, leaving a dark red mark behind.
Strengths: Can cut through most material and low ranked armor.
Weaknesses: can't cut through most armor.
Cooldown: 1 turn.

Name: theif.
Description: Pounce stealthily approaches the target and quickly snatches an item that weighs less than himself.
Strengths: Doesn't make a single sound and fur blends in with the shadows.
Weaknesses: If he is notice he will turn around and quickly retreat.
Cooldown: 3 turns.

Name: Clara's weapons are her celestial spirits, Ursa Minor.
Rank: Ursa Minor is a B-ranked spirit.
Type: spirit
Description: Ursa Minor has long blue hair like the night sky and wears a sweater and skirt made out of brown fur. Also has long brown boots and bear ears and tail. She is usually stubborn and rude and tries to protect her master from anything.

Strengths: She will do anything her master says without complaint. The more angry she gets the harder she becomes to defeat.
Weaknesses: When it's cold she gets sleepy like as if she needs to hibernate.
Abilities:
Name: Grizzly claw
Description: Ursa Minor turns her nails into long, sharp black claws and slashes her opponents.
Strength: Can cut through steel
Weakness: Gets hot in fire and burns her hands.
Cooldown: 1 turn.

Name: Polar fang
Description: Her teeth become longer and she runs at the enemy and sinks her fangs into them.
Strength: Can crush almost any armor besides high ranked ones.
Weakness: Only lasts for ten seconds, forcing her to take her teeth out quickly.
Cooldown: 3 turns.

What rank is this pet?