The Manx were once Hellbent. In ancient times the Templar fear that the Hellbent would escape the Hellholes, so they took several Hellbent Prime and had them breed until the results were the Manx. A ferocious line of hunters who above all, searched for any escaped Hellbent and kill them upon sight. 
 

Encounter with Moon Knight

In recent time the Manx were let out of there pit to hunt for the Hellbent that lurk New York. Where they tracked Moon Knight down the a church slaying Network, at which point Murmur fled. The Manx informed Bloodline, that doom was coming for him but not tonight, the Manx escape through a hole and Moon Knight tried following but he was unsuccessful.
 

Powers

The Manx have no scent, as not even Jack Russel could track them. They are vicious creatures with supreme strength, sharp claws, teeth and agility similar to a werewolf, however they posses an imprinted hatred of the Hellbent and will try to slay them if they even as see one.  As remark by the Templars, the Manx have a mind and are not it all brute as the 13th generation of when rogue. They do not posses much stamina and can be killed if stabbed through any major organ, the problem is actually hitting them do to their speed.