Thanks for the upload! Good to see that he spent those 4 hours thinking of a game plan, and realized what was going on. That dagger is OP though, usually weapons would have a armor penetration passive or even armor shred, but this one straight up amplifies your damage. Although the damage amp might just be making up for the damage lost due to the high defense, so maybe it isn't that OP, but for what he paid for it I don't think you can really complain about it. I wonder if the author did any research on blade edges though? I am far from an expert but why would a serrated edge knife be better than a non serrated edge against armored enemies?
That Dagger Throw skill is also interesting. He did it before having the skill, so the system gave it to him? Also what dagger did he throw? Before he throws it, we see him summon a weapon in his left. So it can't be the one he just bought. Maybe it is his previous blade? I doubt it was some random blade because after he threw it, then he learned the "Dagger Throw" skill. I'm going to assume the reason it consumes mana is because it pulls daggers from the aether using mana.
Also hope he makes it to the parent teacher conference.