Criminal Minds: Evolution is up and running after much anticipation, and some of our favorite BAU agents have returned to our screens after a brief hiatus. Whilst favorites such as David Rossi (Joe Mantegna) and Emily Prentiss (Paget Brewster) are back doing what they best, there are a couple of noticeable absentees. One of these missing agents is Dr. Spencer Reid (Matthew Gray Gubler). As well as this leaving the show feeling as though something is missing, given Reid has been in every single season, it has also changed the dynamics of the group. His relationships with his colleagues gave the series a lot of heart and a personal feel, and one of these relationships was stronger than most.

Jennifer "JJ" Jareau (A.J. Cook) has throughout the show's tenure been one of Reid's closest confidants after the two have worked hundreds of cases together. Reid has previously shown romantic interest in JJ, which later blossomed into an unbreakable friendship, and he was even made the godfather of JJ and her husband Will's (Josh Stewart) son, Henry. As a result of this friendship, JJ is one of Criminal Minds' most lovable characters as her caring nature and compassion towards others has been allowed to be fully fleshed out.

This has always allowed for an opportunity for JJ to add an extra dimension in her character development, and so without Reid, a question is posed. Can JJ still show this side of her personality? Fortunately, through the increased presence of Will in the new season, the writers have been able to further develop the personal side of the character. This need for another person is no slight towards JJ as an individual, or to Cook and her stellar portrayal of the much-loved agent, but somebody to care for is always going to be necessary to achieve this, and that's what makes Will essential to the series.

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Will Is an Essential Character to JJ's Story

AJ Cook as JJ Jareau with Josh Stewart as Will in Criminal Minds at their wedding
Image via CBS

Will LaMontagne was first introduced way back in Season 2 and has been a recurring character ever since. We've watched as his romantic relationship with JJ has grown, and eventually blossomed into a family, but despite this, his appearances have been sporadic. Popping up in an episode here, an episode there, it's been hard to truly gauge how important he is to JJ, but that's changed with Evolution. Will has appeared in every episode of the season so far, giving us more of an insight into one of the show's most stable relationships.

Times are seemingly tough for our loved-up couple, with numerous instances pointing to a lack of alone time between the two. Between JJ's work, unexpected meetings, and their children, JJ and Will have found that moments of intimacy are becoming fewer and fewer, which would potentially be the cause for a rift in a relationship. However, this is allowing JJ to show a determined and passionate side outside of her job at the BAU. She has become determined to make time for Will, which further highlights how much he means to her. It's never been doubted that JJ is fully committed to her job, and has always been determined to do the best she can, even putting her own life on the line at times, but the presence of Will is allowing for this to be seen in her personal life. This gives a layer of complexity to her character, showing exactly the kind of person she is.

Will's Storyline With His Health Offers Another Path of JJ's Story

AJ Cook as JJ Jareau with Josh Stewart as Will in Criminal Minds
Image via CBS

Another way Will is being used to develop JJ's character is the worrying storyline of him potentially facing a serious illness. This has of course caused a deep sense of dread for the pair, but it seems to be affecting JJ a lot more than Will. He seems to be more accepting and unsurprised by the news, whereas JJ has uncharacteristically shown signs of panic. She has almost always kept a cool head, even in the most nerve-wracking situations, but the thought of her husband facing a struggle with his health is looking to be one step too far. This is something that we don't often see with any of the show's characters. Whilst some cases can get personal and emotions can run high, for the majority of the time our agents are able to switch off their emotional side and focus on the job at hand. As previously mentioned, Reid has been a conduit for JJ to show this side, and so a storyline like this involving Will is crucial in Reid's absence to allow the writers and A.J Cook to fully boast JJ's personality.

Will's presence in this series has also brought out a trait in JJ that we've rarely seen at all through the previous 15 seasons - fear. After a discussion of Will's medical issues and the importance of being more open with each other, the couple made an agreement that JJ would call Will at times she thought she might be facing a dangerous situation. The mid-season finale showed us this pact in action, as JJ rang Will before investigating a suspicious shipping container. A.J Cook did a great job here, as she really encapsulated the emotions someone in JJ's situation would feel, and brilliantly portrayed a sense of fear in what was a very brief call. Worry has often been an emotion shown by the agents, but fear is rarely demonstrated. This is again down to JJ's marriage. When working as part of the team, each team member is in roughly the same boat, and on a professional level, this sort of reaction is never shown. However, due to the agreement made with Will, JJ takes a minute to think about her emotions, and shows us as viewers that she is susceptible to all the same feelings anybody else would be.

Through her previous connections with Reid, and now with Will's increased presence on the show, JJ has become one of Criminal Minds' most complex characters. We've seen glimpses into the personal lives of all the agents in the BAU, but not one has developed as intricate of a personality as JJ, and that has to be credited to the supporting characters in her life. It's always intriguing to observe her personal life, and it's a huge positive that Will has been appearing as a series regular in the rebooted series and his presence is very welcomed.