In my opinion, Warlow is the first ever vampire/warlock and belongs to the first coven of warlocks on earth, which the name warlock probably originated from the warlow family. Im guessing he found a spell to become both, and a spell to make him virtually indestructible to the true death. However I think he couldnt find a way to counteract the sun, but through Sookies blood and a ritual, he can finally turn into a truly immortal creature of the night. Its also possible vampires like Russell and Lilith fear Warlow because he did the one thing they never could do.
Tommies breakdown of Warlow:
(In Human years-early to mid 20's)
(In Vampire years-thousands of years old, older than russell)
I think he is most likely an average built man, 6ft tall and weighing around 200 lbs. His hair color and eye color could be of any kind. He is probably using a spell to disguise his voice and using a spell to astral project as seen when he threatened sookie. Finally the M in his name is most likely Matt, Mark, Martin, Michael, Malachi or even Mister Warlow and his real name is disguised as well.
Thats my thoughts of M. Warlow. What do you all think?