Within a Fort Leonard Wood chaplain's assistant rests a dormant beast, an alter ego not unlike the one depicted by an action figure atop his desk.

Sgt. 1st Class Jeff Duncan doesn't have the appearance or the attitude of an aggressive Soldier. His bright smile and playful laugh portray a kind-hearted attitude. But there is another side to the Nashville, Tennessee, native.

Duncan compares himself to Bruce Banner in that both are mild mannered, sensitive and intelligent, but like Banner, Duncan has a "Hulk" within that is unleashed when needed.

The transformation takes place when Duncan is competing in the Modern Army Combatives Program.

"The 'Hulk' comes out for a specific purpose," Duncan said. "When the cage door shuts, then my 'Hulk' comes out. When it opens, I can be Bruce Banner again," he said.

Outside of competing or training in the gym, Duncan prefers to be with his Family or helping with the religious services on the post. Both are reasons Duncan joined the military.

His path to the Army started as a wrestler in high school. He was physically fit, hard working and looking to support his Family. His scores on the Armed Services Vocational Aptitude Battery were high enough for the recruiter to offer him just about every job available.

The recruiting video about the chaplain's assistant caught his eye. He had attended church services regularly growing up, thanks to his mother's insistence on a weekly basis.

"My mom used to drag me to church, literally," he said. "Every Sunday we were there. Even if my friends and me went out and everybody's crashed out on the floor on Saturday night, whoever was in the house on Sunday morning, you were going."

In the video, Duncan saw the chaplain's assistant setting up worship services. He saw them passing out literature to Soldiers in the field.

He saw it as a way to fulfill his desire to help people, and his mother saw it as a way to keep him out of harm's way.

"She was elated about that, because she was thinking about my safety," Duncan added. "My mom figured I would be in a chapel setting up services, passing out candy."

Being a chaplain's assistant turned out to be more than Duncan expected, but for the good, he said.

"The chaplain's assistant needs to be very diverse, a jack of all trades," Duncan said. "Depending on what type of unit you are assigned to is what your primary functions are going to be."

Duncan has served at locations where he was primarily in a chapel setting, and he has served in infantry battalions where the commander's intent was to be ready for deployment and combat at a moment's notice.

While in an infantry battalion at Fort Drum. N.Y., the Sept. 11 attacks happened, and changed the mindset of what it means to be a chaplain's assistant.

"Back in 1997, we were trained on a lot of administrative tasks," Duncan said. "(After the attacks) we needed to shift our focus as chaplain's assistants. We are the chaplain's personal security."

At that point, Duncan became more interested in things like advanced marksmanship and Army combatives. He wanted to ensure he would be the best possible assistant to the chaplain as he could.

Duncan said it's important to the chaplain, and their spouse, to know their assistant is capable of helping to ensure they come home. Having the extra training goes a long way to help with that.

To add to his protection capabilities, Duncan began to "dabble" in various forms of martial arts while stationed in Korea.

He was approached while working out in the gym about being a wrestler, and if he would be willing to exchange jujitsu lessons for grappling lessons, Duncan said. It grew from just two of them to four of them, including someone teaching boxing and someone teaching Taekwondo.

It was while he was in Korea that Duncan first qualified for the All-Army Combatives Tournament. He has since returned to compete four times, finishing in the top five, three times. He said he has won at every combatives level the Army has to offer, except the All-Army championship.

Duncan was stationed at Fort Leonard Wood for his first of two tours when the Army had its last All-Army tournament in 2012. Duncan got close to reaching the finals, missing out by just one point on a split decision. He said he worked as hard as he could, training every day to get the opportunity to return, but the Army stopped holding the tournament.

Following a one-year assignment in Korea, Duncan returned to Fort Leonard Wood to his current assignment and picked up right where he left off in 2013, preparing for the time when the Army would bring back the All-Army tournament. The Army did just that, announcing the return of the tournament in 2017.

Duncan qualified by winning in his weight class in the post tournament in true "Hulk" fashion, by forcing his opponent to tap out in less than one minute in the first round. However, the tournament was postponed from its originally scheduled date and now falls during his terminal leave before his retirement.

Although Duncan will miss his final opportunity to compete at the All-Army tournament, those around him at Fort Leonard Wood say his career was a success.

"Sgt. 1st Class Duncan always provides a calm, professional presence and can be counted on to bring the voice of reason to difficult situations," said Chaplain (Lt. Col.) James Paulson, Maneuver Support Center of Excellence deputy garrison chaplain.

"He has been a great leader and mentor to our young chaplain assistants as well as a strong and dedicated assistant to the chaplain and civilians," said Beth Shamhart, Religious Support Office, administrative assistant. "I am going to be sad to see him leave in the spring when he retires, but know he will be extremely successful in his next chapter."

Following his retirement, Duncan plans to return to Korea to continue helping others by working security and training those interested in martial arts and combatives.