A Helping Claw
Completing the quest will unlock the Guardian Flail as a weapon for Link; as well as the EX Link: Flails, EX Seeking Wooden Swords, EX A Spear Experiment, EX The Squad's Training Retreat, The Blazing-Blue Blades, and Magnificent Mass quests.
"Something's been on my mind lately... Why not use the unfathomable power of ancient relics to craft a tool for fighting the Calamity? Hm? Yes? I've been eyeing Guardians in particular..."
"At last... it's finished! The Guardian Flail. A weapon boasting the strength and dexterity of a Guardian. Link! If anyone can master this MARVELOUS weapon, I'm certain it's you!"
- Obtain Guardian Flail