Hey hey, it's Christa again, bringing in Valerian Mulciber. He's a Slytherin, class of '76, a Death Eater, and obsessed with tormenting Mary Prewett. Up until about a month ago he was working as a Healer in the Spell Damage Ward of St. Mungo's.
Then he idiotically ran headlong into a setup of Mary and Dorcas' (and roped Evan into it as well), and wound up being unmasked. Since then he's fled his job and home and has been hiding out in the Scottish Highlands with his dog, brooding away and biding time until he can make another attempt on Mary's life. He's not a very pleasant person, has very few friends as he doesn't think most people are worth his time, and is not looked upon very well right now within the DE ranks due to his impetuous attack.
His full profile is right over
yonder, so have a look and we can plot out some relationships! He'd probably have had contact with fellow DE's (shocking!), St. Mungo's workers, and random victims.