Shortly after they were done with farming, they decided to head back, John planned on eating a reasonable amount, so that he would have enough energy to fight, and not start puking everywhere if he was hit too hard.
On the way back, he also began thinking of a plan. Now that he had posession, and could use the dark version every element, he would most likely win in a magic fight, but this was a no rule fight.
Master could simply shadow step away from everything he would throw at her, so there was three options.
The first option was to restrict her then finish her off. Which was easier said than done, as she could withstand gravity x 30 and possibly 50 which was the highest john could do, before collapsing due to magic exhaustion
[I need to think of a new restricting spell...] John thought to himself
Kinetic Energy: Energy an object or being posseses due to it's motion.
Chemical Energy: Form of potential energy which is stored in chemical bonds.
Long chapter explanation of a spell, but most of you have been requesting a better focus and scientific explanation behind the way john's spells work.
Don't worry, it won't be like this for every spell, it's just that this one was a very complicated procedure, even for john.
And yes, this is something which 14 year olds learn at school. I learnt it at that age.