Slifer's is all about having cards in hand to power it up and anyone trying to attack it will often find themselves 2000 ATK points weaker, Obelisk is about having monsters on the field to sacrifice to nuke the opponent's field and Ra can big itself up depending on the number of Life Points you have or you can sacrifice Life Points to destroy your opponent's monsters and if you summon it through the effects of The Winged Dragon of Ra Sphere Mode, you can get over Ra's weakness of its contradictory effects by having Ra at 4000 ATK points if summoned that way
More information about Legendary Decks II can be found on Konamis official website.
Although it can take some time to set up in-game, investing time into obtaining the cards for this deck is worth it
Don't miss out on your free spend!
While the Fairy type attacker, Xerneas EX (EX), was not that great, its support engine of Aromatisse () and "Baby" Xerneas were promising cards
For the side deck, my favorite techs were Network Trap Hole, Super Anti-Kaiju War Machine Mecha-Thunder-King, and Zombie Necronize