The former Law & Order: SVU star will play Roman - the 500-year-old head of the Vampire Authority - in the HBO drama's fifth season.
"Roman's determined," Meloni told TV Guide. "He wants peace, but others have been trying to stomp out his path. Think [Barack] Obama with very long incisors."
The actor added that Roman is somewhat similar to his SVU character Elliot Stabler.
"Elliot was free-form [and] Roman's more thoughtful, yet unafraid to pull the trigger," he explained. "He's a man of action. Get the facts, get it done.
"But they both have a certainty of their view. They both think they're right."
It was recently announced that Nurse Jackie exec Mark Hudis will replace True Blood creator Alan Ball as showrunner.
The new season will premiere on Sunday, June 10 at 9/8c on HBO. In the UK, True Blood airs on FX UK.
> True Blood: Bill, Eric battle The Authority in explosive new trailer
Watch Christopher Meloni in a new True Blood promo below: