Kennedy the Mouse

Backstory
Falling ill to a lethal disease at a young age, he eventually died after three weeks. However, this was far from the end of his story, he met an ancient spirit called Kronos. The Guardian of Spirits was in search of a champion to help fend off a coming threat that would upset the spiritual balance of Mobius. To ensure its safety, there must be a guardian, and Kronos had chosen Kennedy, believing he had the soul for the job. In order to give him the resources necessary to combat the coming evil, Kronos turned himself into a massive, mystical blade. While in possession of Kronos in his sword form, Kennedy has unlimited access to the spiritual forces around him, and as a spirit being he's basically immortal. With a plethora of physical spiritual powers he prepare himself for the coming threat; and decades later it has finally come and for thousands of years he has battled these mysterious forces.

Personality
Kennedy is often a kind and well-mannered individual whose sweet nature is offset by his years of experience on the battlefield. This experience has made him a bit more tough than he was in life; instilling a sense of duty in him as well, Kennedy fights off demons with a tenacious fury. He likes peace and quiet, helping out lost souls and walks across the universe. Kennedy does not like violence, in fact he tries to avoid a combative confrontation as much as possible; much to Kronos' dismay. He is also not fond of demons who make his job more tedious than it has to be.

Kronos
His mentor and friend, Kennedy sees him as a father.

Demon Legion
He simply sees the demon race as an adversary he needs to overcome, he has no real gripe towards them personally.

Spirit Physiology
Kennedy is a spirit, as such he is intangible, invisible, and inaudible to living beings. He is also immortal, mainly because he can't die since he's already dead; but also due to the fact that while he's in a living body, being in possession of Kronos will keep the body alive. Kennedy can also possess living and nonliving things, and is a master in the use of spiritual energy. He can generate, shape, and manipulate spiritual power, which is generated by every sentient being that possesses a soul, or in places with powerful spiritual influence. He can convert it into various forms of energy, manifest it into solid form, or merge into existing objects.

Swordsmanship
Ken is a master in sword fighting, his millennia's worth of experience can attest to that. He's so skillful, he can wield multiple swords at once. Kronos, in his sword form, gives Kennedy immortality and amps his mystic arts. He also has a sort of "loyalty lock" on him that prevents others from using him through a number of means from weighing himself down to absorbing the targets life-force. Haruko & Tsukiko are magical dual swords that can control sunlight and moonlight respectively.

Magic
Kennedy has the power to use of rituals, symbols, actions, gestures, and languages to exploit supernatural forces to varying degrees, with only his skill, personal power-level, imagination/knowledge, and/or morality to define the borders. Given the flexibility of magic, he essentially has unlimited possibilities for what to do with it.

Trivia

 * The cloud he rides on, Aria, was inspired by Dragon Ball's Flying Nimbus.