A power of Tao is always linked to its wielder's skills and personnality. This power calls upon its wielder's ki (life energy) and needs a difficult and extremely rigorous training to be fully mastered. Using carelessly a power of Tao without proper training would consume its wielder's ki; and if someone were to use an untrained power of Tao continuously his/her ki would end up depleted, leading to his/her death.
Every Apostle of the Star masters his or her power to the point of perfection and gains from it immense might and beyond-human fighting abilities; putting them on an equal footing with the Chrono Numbers themselves. (Chronos' elite military brigade: a group of thirteen supreme warriors, each one of them being unmatchably skilled in the use of a particular sort of weapon.) Aside from their unique power, the Tao wielders also gain the ki-based abilities that follows. (However, few of them are seen using it.)
chi is the life energy needed to use tao abilities. It exist in all living creatures, and when it is depleted in great amounts, it leads to death.
Inner chi kung People who use inner chi kung exel in controlling ki within the body.
Outer chi kung People who use outer chi kung release ki outside the body.
Soft chi kung is one of the tao techniques that uses the power of ki to accelerate cellilar functions. Kyoko's heat is mainly an application of this technique. In the manga, by sending his ki into Train, Doctor forced soft chi kung to occur, and healed his wounds.