Bad With The Spear.

These three groups of weapons are the most used weapons by battle sage monkeys and will ensure that he will have a wide array to choose from.

He used a dagger in his past life because of its lower requirement for technique and its reliance on agility rather than strength. But the dagger is more suited to assassination and will be ill-suited to cutting off the necks of a hydra. He is sure the familiarity with it and his speed will allow him to slip by the hydra but he doesn't want that. He wouldn't be able to challenge himself and he wouldn't be able to continue using the dagger when his divine ability awakens. Battle sage monkeys don't use daggers.