Here's how to get this game's equivalent of the champion tunic (champion leathers)
You'll need enough stamina food to give you at least a second wheel of stamina
Once you have that, go to the lookout landing tower and use it to launch yourself into the sky. Then just glide to the top of the castle, there aren't even any enemies there.
Go to the two torches in that room and light them, then a box will open with a chest containing the champion leathers. It gives five defense so it's a quick upgrade from the hylian tunic and zonai tunic early on
