Jeff seeing the incoming danger matched his charge speed by flying back away from him at the same speed of Seras charge, thus keeping him from being able to close in the distance. He then proceeded to fire off 3 wind sage boosted wind scythes with his kicks before firing a plasma bomb at Sera and time it to explode the second it came into contact with him. The bomb itself was also wind boosted to counter. 
"You are gonna have to try a little harder then that." His voice echoed loudly towards him. It seemed to be more then just a taunt as the burst of wind that came from it as it acted as a shockwave of its own.