alastor (shakugan no shana)

Alastor, called the Flame of Heaven, is the Crimson Lord bound by contract to Shana in Shakugan no Shana. Stern, proud and rather formal, he advises and scolds his partner through a talking pendant. Most fan art shows him as the Cocytus, a pendant on a necklace glowing with fire, and rare pieces depict his towering true form with enormous wings and horns.