For this list, I'll go over boss monsters that are either too hard to bring out for what they do, or just have very lackluster effects. With most of the really bad boss monsters being a combination of both. The list: 10: Red-eyes Darkness Dragon 9: Gate Guardian 8: Armityle the Chaos Phantom 7: Armed Dragon LV10 6: Elemental HERO Divine Neos 5: Neos Wiseman 4: Meklord Astro Mekanikle 3: Helios Trice Megistus 2: Machina Force 1: Spirit of the Pharaoh