Flame Orbs are the small ammo type used to power Heretic's Phoenix Rod. They provide the player with different amounds of ammo depending on their source. Pre-existing Flame Orbs only provide 1 shot, while those dropped by Ophidians provide 5 shots, and if a Maulotaur drops one on death, it's worth 10 shots, same as the Inferno Orb.

Heretic Items Health Crystal Vial Quartz Flask Mystic Urn Armor Silver Shield Enchanted Shield Weapons Staff Elven Wand Gauntlets of the Necromancer Ethereal Crossbow Dragon Claw Hellstaff Phoenix Rod Firemace Ammo Wand Crystal Ethereal Arrows Claw Orb Lesser Runes Flame Orb Mace Spheres Crystal Geode Quiver of Ethereal Arrows Energy Orb Greater Runes Inferno Orb Pile of Mace Spheres Items Crystal Vial Map Scroll Bag of Holding Ammo Keys Artifacts Chaos Device Morph Ovum Mystic Urn Quartz Flask Ring of Invincibility Shadowsphere Timebomb of the Ancients Tome of Power Torch Wings of Wrath