YAVORIV, Ukraine-- When the U.S. Army's 45th Infantry Brigade Combat Team assumed the Joint Multinational Training Group-Ukraine mission in January the Combat Training Center development staff was tasked with growing a small group of Ukrainian soldiers into a formidable opposing force.Ten months later, the OPFOR, composed of Ukrainian soldiers permanently stationed at the Yavoriv CTC, has grown from a little more than 100 soldiers to a battalion-sized element complete with a T-64 tank company.The role of the OPFOR, explained CTC development officer, Lt. Col. Khalid Hussein, is to simulate the enemy, thereby creating tough and realistic training for the infantry battalions that rotate through the Yavoriv CTC."Our goal is to have a fully-functional, free-thinking opposing force that is capable of creating a challenging environment for the rotational unit and we do this through the application of a force-on-force scenario," Hussein said.Tools such as the Multiple Integrated Laser Engagement System, more commonly referred to as MILES gear, help simulate battlefield effects, but it's the unpredictability of the actual OPFOR soldiers that makes the fight feel real.Enabling the OPFOR to become what it is today has not been without its challenges."The biggest challenge has been growing from a company-sized to a battalion-sized element in a very short amount of time," Hussein said. "Anytime you expand an organization-personnel issues, training, resources, logistics-these are the natural challenges you'll face."Hussein credits the OPFOR's success to the professionalism and adaptability of the Ukrainian officers and NCOs who have stepped-up in leadership roles throughout the formation."We capitalize on the experience these guys bring to the unit," Hussein said. "They have responded very effectively and it's been quite amazing how quickly they've adjusted."Over the last year, the deployed U.S. Soldiers have stressed the importance of the NCO corps to the Ukrainian army through NCO professional development.The NCOs in the OPFOR unit are no exception."My main focus has been showing them how NCOs and officers work hand-in-hand," said Sgt. 1st Class Russel Coley, the NCO in charge of the OPFOR development.In the beginning, he explained, it was difficult to convince the Ukrainian officers to trust their NCOs, but now, slowly but surely, the NCOs are leading more and more of the training."We've integrated ourselves with the Ukrainian OPFOR, we're like one team," Coley said. "Now they want to model their NCO corps after ours."As part of their professional development, Coley has had the Ukrainian NCOs lead classes on tactics and pre-combat checks and inspections among other topics.Coley says building a strong OPFOR hinges on their NCOs being proactive."That's the key thing-they're taking ownership of it," Coley said. "They can see the fruits of their labor and they know that what they're doing is paying off."