Everyone on the sidelines: wow such big brain tactics of hitting the same spot repeatedly! No one in the history of mankind has ever thought of something like that! He's a genius fighter!
edit: @SomeGuy1 Sure it is, you just have to apply a force through the leg that counteracts any rotation induced by gravity (aka falling while keeping the leg straight). Meaning all it needs is something akin to a wheel-axis in the knee-joint that tries to spin the leg in opposite dir. Sort of like how unicycling works, except the wheel is stuck (on the ground), so only the top half can move.
It's not like he has any other choice. He isn't as strong as nor as gifted as Seran in swordplay and he has a pretty shallow pool of mana (at the moment anyway), so his go-to tactic is just overwhelming the opponent with gigantic cache of magic stones.
@itsjenyoumen He's using his special power of being obscenely rich. If you have enough money to buy explosives to deal with your problem, all you need to do then is keep your opponent in one place enough for you to blow them up.