Interesting trick, I'm guessing the kid hid the voodoo reflection as he didn't want to show it and it takes preparation for every hit or have a short effect.
It being possible to trigger by himself makes it very vicious.
MC should have tested if it had a area of effect.
As the sturdio didn't draw the damage points is hard to know if MC was getting the full damage or only a partial reflection, or it was all just in his mind and the body responded to the brain signals.
I think the MC should get some aura in the future to use undeads, but just a bit so he can make a small summon to prove to being a necromancer.
Can just bullshit that he doesn't need to summon more powerful undeads or that through his hidden talent he can directly enpower himself in exchange to not make a summon, no need to announce how he can't do it at all.
I presume he didn't use his bonus stat points because the aura needs to be at least above zero to be raised, possibly a system failsafe to avoid a warrior wasting points by mistake on a class dead stat.
And his bonus point only gives points by killing the enemy in melee, and he can't change what stat the point goes.