Nick's darker side will be revealed in the upcoming fifth season of "Grimm." 

The fourth season of NBC's fantasy police procedural series ended bad for Nick (David Giuntoli), after his mother Kelly (Mary Elizabeth Mastratonio) died in the hands of the love of his life Juliette (Bitsie Tulloch), who was transformed into a highly dangerous Hexenbeist. 

While Nick could have made Juliette pay for killing his mother, he contemplated doing it at the last minute before the end of season 4. But Trubel Rubel (Jacqueline Toboni) decided to finish his job by shooting an arrow right through Juliette's neck. 

However, losing two important women in his life is not the end of Nick's problems. In "Grimm" season 5, the Grimm will have to face Adalind's (Claire Coffee) pregnancy, since he is the father of her unborn child. Will this change Nick's game next season?  

"Well, something's gotta happen, one way or the other," series creator David Greenwald told TV Line. "He's gotta be responsible for the child."

Executive producer James Kouf added, "He's got a child and he's got to step up at some point. He knows he can't abandon his child. He was abandoned." 

Could his still unborn baby make him forget all the pain that he experienced last season? This is not likely to happen since the co-creator said Nick will be enveloped in grief.

"I think it's going to be even darker still in a way. You know, it's not going to be the same 'Grimm'. I think it will be even bigger, even darker, even weirder. You know, I think it's where it naturally will go," Greenwalt said in another interview with The Hollywood Reporter. 

Kouf also revealed that the detective will wallow in his sadness by sitting alone and grieving inside a room.

"Grimm" season 5 will begin filming in the coming weeks, and the premiere episode is set to air in October.