Callen's life-long quest for his family lead him to his father's doorstep last year, resulting in an NCIS: Los Angeles reunion seven seasons in the making. Now that Nikita Reznikov is finally back in the picture, he isn't about to fade into obscurity once more.

Grisha's (Chris O'Donnell) father will return in season 8, according to TV Guide, but the reasons behind his appearance are unknown. What we do know, however, is that Callen's inquest into his past won't end simply because he learned his given name.

"It was always my intention to reveal Callen's identity before the series ended," executive producer Shane Brennan told Entertainment Weekly. "We've had a lot of fun finding out who Callen is, and from where he came...And while he's now discovered his identity, Callen's odyssey isn't over. In many ways, it's just beginning."

In the meantime, Callen and Co. will need to deal with the OSP's latest mole. Granger (Miguel Ferrer) and Hetty (Linda Hunt) kept discussion of the leak to hushed tones in season 7, but when season 8 begins the situation will reach a boiling point.

"In the season premiere, the NCIS team is under investigation by the Under Secretary of the Navy due to the identification of a mole in their department," CBS teased. "With every move being monitored, the team is assigned a High Value Target case involving a Syrian terrorist."

Are you excited to see more of Callen's father? Sound off in the comments below!

NCIS: LA will return to CBS on Sept. 2 at 8 p.m. ET.

Tags: NCIS: LA CBS television NCIS: Los Angeles