
This is what I got, could be wrong. Our Ciel is Sirius, but he is not the guy getting blood from the blood bank, that's evil Ciel. Evil Ciel was playing the part of Lord Sirius, but when the crimes and murders started coming to light, Evil Ciel framed our Ciel/Sirius. Our Ciel is Sirius, but he is being framed for things Evil Ciel did under his name. I hope I'm not remembering incorrectly

Sirius A is a bright blue star in the constellation, Canis Major. If you find the three stars that form Orien's belt and follow with your eyes downward in a straight line toward the horizon, you'll find Sirius, the brightest star in the night sky. Canis Major is said to be one of Orien's two hounds who chase souls across the night sky.
Sirius, might be recognized as associated with Anubis the dog-headed god, Hermes, Mercury, and the angel Gabriel.
The star, Sirius A is half of a binary. Sirius B is a tiny white dwarf. I believe they make a full revolution around one another every 50 years if I remember correctly.
Since it will be a while before we know our ciel's real name give us some names that could fit for fun XD