Black lotus

They key component needed to make explosives strong enough blow open the portion of Mt Tomo that the ROD is trying to get into.

takes approximately 6 months to grow.

ALWAYS found in the North. Knowing where black lotus is means that you cannot give exact directions of that known location. Such is the curse if the black lotus.

Because there is no exact location for it unless you learn to grow it yourself. Super rare since nobody seems to look for it.