If you're HR6, you have to clear Battle Training quests, total of 10 monsters with at
least one weapon each. Here's the list:
Yian Kut-ku, Congalala, Khezu, Daimyo Hermitaur, Blangonga, Yian Garuga, Tigrex, Diablos,
Gravios, Kirin. (Hunt them first before you can unlock the training quest)

If you're HR9, you have to clear G-Rank Training quests, total of 8 monsters with at least
one weapon each. Here's the list:
Hypnoc, Emerald Congalala, Plum Daimyo Hermitaur, Nargacuga, Lavasioth, Copper Blangonga,
Terra Shogun Ceanataur, Volcano Rajang. (Hunt them first at G-Rank level before you can
unlock the training quest)

Volcano rajang is hard!

that is one very overpowered monkey ever to live i hav 2 beat 2 of rajang at once in 50
min dam thats not going to be easy