Aspen

Aspen (アスペン, Asupen) is Fergus' pet cat. Just like him, she lives on Athelney and often accompanies him on his job to patrol and clean the school.

Appearance
Aspen is a gray mackerel tabby cat with yellow eyes.

Personality
Aspen is described by most students to be unpleasant, having a personality similar to Fergus, and this being the reason they get along. In fact, she is said to "often pop up randomly from the most unlikely places", especially when a few students are alone. Alongside that, she tends to interrupt conversations, especially during the meals, where she likes jumping over the tables.

She is also exceptionally intelligent, being as knowledgeable of the school surroundings as her owner, and thus, being more than able to find students hiding in places, no matter how sneaky they are. Many are scared of her and find her behavior disturbing, while others hate her and find her annoying, as much as Fergus. Aspen is fond of Fergus and always obeys his commands. In her free time, she likes roaming around the school and hunting for birds.

Abilities & Powers
Aspen is noted to be really good at her job of finding students who are hiding, perhaps even better than Fergus himself; this is mostly due to her enhanced senses and ability to fit in small places.

Impressive Speed and Agility: Being a cat, Aspen is extremely fast and agile, can leap very high and access high places or capture preys on the air (which she often does when catching birds). She can achieve a jump of approximately six times the length of her own body, and, being a cat, she can also jump down or fall from high places without getting hurt, as she is able to twist her body into a proper position and land on her feet.

Enhanced Sight: Possessing a tapetum lucidum, which improves her ability to see in the darkness. She is good at detecting movement even in low light, and she is also nearsighted, which is a good attribute when hunting to capture preys. She also has a field of view of 200°.

Enhanced Hearing: Aspen can hear much higher-pitched sounds than humans, up to 64 kHz which is 1.6 octaves above the range of a regular human. She can judge within 8 cm the location of a sound being made 1 m away, allowing her to find hiding students.

Immense Smell: Aspen's sense of smell is very advanced like all cats', and about fourteen times as strong as a normal human's. With this, she can easily notice and pinpoint the location of a certain student, and immediately recognize them by their smell.

Enhanced Touch: The numerous whiskers (vibrissae) Aspen has around her body aid her perception and gives her extraordinarily detailed information about nearby air movements and objects with which she makes physical contact with. Basically, she is able to sense near obstacles without it needing to see them.

Enhanced Stamina: Aspen has a high amount of stamina, being able to spend one entire day and night being physically active, and without showing any signs of fatigue. Though, really troubled or tiring nights can take a toll on her, which often causes her to sleep through the entire morning the following day.

Immense Intelligence: Aspen has more than once been noted to have almost human-like intelligence, with many students believing she is, in a sense, self-aware and "knows more than they think". She is able to open doors which are low enough for her, she knows all the secret places in the castle and can locate students in them, she has tailed many students without them noticing and she is seemingly able to understand perfectly all the commands Fergus gives her, obeying them without hesitating.

Nen
It's said that affinity with nature is connected to sensitivity for aura, and animals are more perceptive in that regard than humans; this is also Aspen's case, and she was able to learn Zetsu spontaneously. She also seems to be aware of that, using it mostly when hunting and at night while she is looking for students in the halls. There have also been reports of students who feel a weak bloodlust coming from her whenever she grabs and captures birds during hunting, though only the most sensitive ones to Nen can perceive it.