Setting down his book again, he turned to face the black knight. "I am not a demon," he said, "or at least, not quite. My name is Kestriel the Heartless, and the conjuring of demonic powers is my specialty." He looked the man before him up and down appraisingly. "You have the power," he noted simply, "but not the mastery. Any man can pick up a sword, but no matter how strong he is, the better swordsman will win." He shrugged. "A recommendation, for any further practice. Calling is a far safer means of summoning than opening a door for them; if you open the door, preparations are almost always critical. But if you call them out, then only those you call can come forth."