The physical difference between the two "Ry"s is Dark Ry has solid black eyes, no pupils, no irises, just jet black. He also exudes a "Dementor" aura- sucking the warmth and joy from any area that he is in.
His wand is used from his belt, without being raised or waved, to manipulate darkness and shadow. The wand can effect him as well without being handled, making it hard to know what defenses are in place without testing them.
Any spell cast by him will cause the wand to pulse with bloodred light, though most are cast non-verbally, so as to give no indication of what has been laid about.
(((NON Disclosed Information- No one in play is privy to this information- not even Dark Ry's altered Self )))
2 years ago, while out for a broom ride, Rydel Back was attacked by a Pair of Dementors. Aided by an unknown passing wizard or sorceress with a Lynx Patronis, the Dementors were driven off, or so it was thought. One was Physically destroyed, but not before it had begin to drain Rydel, the Patronis forced the Dementor into him, causing a Merger never before seen.
Rydel has no knowledge of it, or who "saved" him. The Dementor has manifested as a second spirit inhabiting a single body, causing a constant struggle for control. Dark Ry is the dementor Manifestation, and possess some of the Dementors inate abilities, but it is slowly learning to use the powers of the new body it possesses, namely Wand Magic.