Fundamental

Normally, at this time, you should look around the dungeon to see if you missed a key object or something, right?

Either Death's or Edward's conspiracy

Ten is supposed to be simple to maintain, otherwise everyone who unlocks their Nen would die soon after due to a severe lack of life energy. The difficult part is using Ten while sleeping.

Exploding spear

Doesn't his dexterity increase with his control exercises?

What happened to relying on pets to cultivate...?

Has anyone noticed the money is USD? How did the US not collapse?