The defensive spell made it impossible for Jax to get too close to his enemy, and also made his threads useless as the lightning bolts burned them away when they exploded.
He wasn't sure if regular attacks activated it or not. One of the two times he had used it, he had been swinging at the man.
'One of two things has to be true though,' Jax thought. 'Either the spell doesn't activate when a weapon is used, or he has to constantly keep using that spell on himself.'
Just earlier, the young man had chosen to dodge his axe swing instead of taking it head-on to create another lightning explosion, so Jax came to understand just that much, if nothing else.
'Don't jump in recklessly, and you will be fine,' Jax thought. If he didn't get too close, all he had to do was watch out for the fireball and arrows.
Since that was the case, Jax realized he had his own ranged weapon to deal with this situation.