Epigonen, the Impersonation Invader is a crucial card in contemporary TCG ABC decks. The card allows for otherwise dead hands in prior builds to flourish and gives the deck a greater degree of consistency, an expanded level of versatility, and allows for the creation of stronger first turn boards. I've chosen to utilize Dragoon over Destroyer Phoenix Enforcer given the Dragoon's ability to negate, the fact that it can facilitate the swift depletion of your opponent's field and/or LP, and the fact that Dragon Buster already has a quickplay banishing effect. The only problem I see is that both Dragoon and Dragon Buster require you to discard to activate their best effects. While my previous ABCDragoon builds utilized Mystic Mine over Pseudo Space, I've decided to go back to using the latter as it further bolsters consistency given a simple combination of Union Hanger and Pseudo Space allows you to build a suitable board with Buster alongside I:P or a Dragoon summoned by the Verte. The fact that both Dragon Buster and Dragoon rely on discards, something I saw as a weakness in the past, also means that it's beneficial that you can further increase your card advantage by engaging in shenanigans via playing Pseudo Space after already having activated and utilized Union Hanger's effects.
I'm still running a decent line-up of handtraps so as to increase one's ability to stand firm should one's opponent be going first. I'll always have a soft spot for the PSY-Framegear Gamma engine and am still running a copy of PSY-Framelord Omega given how devastating it can be for your opponent if you summon that card after negating a handtrap used against you on your own turn before you've summoned a monster.
I've been thinking over the extra deck but believe Borrelsword is a worthy addition considering how easy it is to summon when utilizing materials left behind by Epigonen's effect. It's allowed me to win on the second turn of a game in a situation where I would have otherwise bricked if I wasn't running Epigonen. Accesscode and the Knightmare package will always be stables in any Link-focused ABC deck, though, considering how easy it is to link climb into Accesscode, itself. Epigonen actually makes such a climb even easier.
Part of me is still considering the benefits of Lambda given how Nibiru can still be a problem should your opponent refuse to wait for Dragoon's summon, perhaps anticipating Destroyer Phoenix Enforcer or some sort of Brandish monster instead, without an Unauthorized Reactivation in hand to protect Dragon Buster. You can still summon a strong Appolousa on your first turn through Epigonen shenanigans if you know your opponent has Nibiru in their main deck or side deck.
I'm still tinkering with my own side deck, though, but I'm not so deluded as to think this deck is the best an ABC deck. that utilizes Epigonen, can offer. There's always room for improvement especially in a game like Yu-Gi-Oh! where the meta constantly evolves.