In this episode I suffer my first death in this run. I got a bit sloppy while fighting the Lord of Flames. Though, my second match went a little better though I did manage to consume almost my entire potion supply.
Thankfully, the item does prove worthwhile despite my initial disappointment since it can be used to create the obsidian orb if you've gathered the rest of the amulets. As for why the obsidian orb is so useful. Well, it gives you an innate resistance to most of the magical attacks that will be utilized by Radaghast and Crrda.
Thanks to the obsidian orb the match against Radaghast was rather easy. Though, he still possess one attack that can bring you to your knees so I'd advice keeping a close eye on your health during this battle.
Afterwards he'll grant you a few Ether Crystals which can be used to turn the final boss battle into a joke.