Shakugan

What they are
A Shakugan is a Being with Arcana of Fire, and they have red hair and eyes.

It is normal for them to hide their power, and one is able to sense other Shakugan around him. Normally, Shakugan do not get along with each other, and one ends up killing the other.

If their hair turns a light blue or worse, white, most wise people stay quite a distance away.

What they can do
Most beings with Arcana are able to Deadbolt, or set a seal to hide themselves from commoners (normally humans) who are oblivious to the truth of the worlds. It is normal to have the power of Yamijaku (Clothe in Darkness), and to invoke the flames. Shakugan call upon their weapons which form through the Arcana.

Most Shakugan do not get cold because of heat they already have naturally generated in their body. Even without invoking their Arcana, they stay heated up, giving off warmth, and are used to heat.