These are the seals of two of my characters, on the left, Gilrandree, the Demon Beast, and on the right, Odontaspis, the Serpent Demon. I'm not really following the traditional meanings of the symbols in the seals (as from the ancient mythology), but trying for the same stylistic look. The left one was originally cast by Laken, though the detail work was by myself, and the one on the right is all my own work. Both incorporate aspects of the visual look of the creature, which certainly doesn't seem true to the original mythology.

For a long time, I've liked the concept of seals for the demonic characters. Again deviating from the original mythology, I view these as graphical representations of the (supernatural) essence of the creatures themselves. These are, all at once, their signatures, symbols of their power, and the symbol (used in a summoning circle) which both calls and binds them. To display them grants them power, but at the same time, confines that power. I'm contemplating a variation where, if one leaves the runes out, just showing the inner circle, it's a symbol of power, while adding the runes makes it more into a binding circle.

This is all my mythology, and nothing based on historical mythology (that I'm aware of), but I still find it rather cool as a thought exercise. And it's fun to draw these up. :)