Well according to TV Line, an a deal has been made. And a few details were given away about Meloni's character, which was described as being a "powerful vampire."
According to the HBO series creator Alan Ball, Meloni will play an “ancient, powerful vampire who holds the fate of Bill and Eric in his hands.” Though there’s still not a lot of details regarding his character on the show or what exact plot he’ll play in the 5th season, one can assume he’ll play the part of a possible new big bad baddy in the series aside from the return of American Horror Story star Denis O'Hare in the role of Russell Edgington.
No official word as of yet when exactly the next season will begin but also joining the cast next season will be Scott Foley, Lucy Griffiths, Dale Dickey, Louis Herthum and Kelly Overton.
Side Tidbit: So how many seasons do you suspect the show will continue to go on for?