Saestrol's video: Hyrule Warriors DE: Where to get Gannon Materials Easiest

This is a fast and very useful method to getting Gannon Materials, some of which are the hardest to obtain. You have to beat Gannon by breaking down his horns, than taking on his form as he attacks and counter with Arrows. This stage is still viable pretty early on, even if you are not terribly powerful. I do recommend this once you are around level 35, or have pretty good weapons. The stronger you are, the faster this will be. You need to also deal with King Dodongo and Ghoma on this map. I highly recommend defeating these bosses first along with any Dinolfos in the way because the chances of Gannon dropping a weapon as opposed to his materials will decrease, and the whole point of this is to get his materials. You can finish this map in a matter of 6-ish minutes if you do things right, or a bit long depending on how strong you are. But this is much faster than the Legend Mode Stage he first appears in. I unlocked the Material Master fairy skill (and it's + variant for multiple uses), which makes this even more beneficial. Activate this skill before you finially finish off Gannon and you will get two drops, hopefully one of which will be the Gannon Horn. If you get the Material Master+ skill, use it on the other bosses to also snag some of their materials, but potentially trigger weapon drops more often (which makes Gannon even less likely to drop one). This is incredibly useful if you haven't gotten 90 Skulltulas yet for the Material Master apothecare mix. Having a material+ skill on a weapon and this stage being a Red Square means that your chance of getting the Horn instead of the Mane much higher. You only really need about 6 Gannon Horns to finish both Link and Youg Link's Badge tree, but Gannon cannot be fought easily at all until you get to this stage. If you need more Manes, fight Gannon without the Material+ skill on the weapon of your choice.