The Phantom Knights have been a very powerful archetype since their introduction to the game, primarily Level 3 Dark Warriors, these monsters combo really well with the Burning Abyss archetype, Level 3 Dark Fiends, as a great Rank 3 strategy. In Master Duel(and the OCG), Number 86: Heroic Champion - Rhongomyniad, a notoriously unfun and unfair card, is legal and fits in perfectly as a Boss Monster in Phantom Knights, as PKs can easily become Level 4 via Break Sword, and make Rhongo, then make Gossip Shadow, as they are all Level 3s, and merge Gossip Shadow into Rhongomyniad to give him a lot of material, and make Rhongo go Bongo.
For the decklist, we have a PK package of 1x Greaves, 2x Gloves, 3x Cloak, 2x Scales, 3x Boots, 2x Wing, 2x Brigandine, 3x Fog Blade, 1x Raider's Knight(and 1x Arc Rebellion), 2x Break Sword, and 2x Rusty Bardiche, we have a BA package of 3x Cir, 1x Alich, 1x Farfa, 1x Graff, 3x Scarm, 1x Dante, and 2x Cherubini, my preferred Handtrap lineup of 2x Nibiru, 3x Ash Blossom, 2x Ghost Belle, 3x Maxx C, and 2x Veiler, 2x Fairy Tail - Snow, 3x Tsuchinoko, 3x Tour Guide, 2x Jackalope, 3x Galaxy Cyclone, 3x Grass, 1x RotA, and 2x Called By, for the rest of the Extra Deck, we have 1x Chaos Ruler, 1x Rhongomyniad, 1x Leviair, and 1x Underworld Goddess