Whoah, I'm the first one with news on the set after Gladiator's Assault! YAY!
Here are the cards that are known so far, and my ideas on them:
PTDN-JP006
Yubel
Dark/Fiend/10/0/0
This card cannot be destroyed as a result of battle. When this face-up Attack Position card is attacked, inflict damage to your opponent's Life Points equal to the ATK strength of that monster. The controller of this card takes no Battle Damage from a battle involving this card. Tribute 1 monster during each of your End Phases. If you do not, destroy this card. When this card is destroyed by a card effect except its own, you can Special Summon 1 "Yubel - Das Abscheulich Ritter"" from your hand, Deck, or Graveyard.
Yep, the Big Bad from Season three of GX is now a real card. As for how useful she is... Well, she needs her own deck to really be good. But she's easier to summon than you might think. One Mystic Tomato is all you need, then you can really get started. You'll need to use a lot of Token Monsters, but a Yubel Deck could work if you worked hard at it.
PTDN-JP007
Yubel - Das Abscheulich Ritter
Dark/Fiend/11/0/0
This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except by the effect of "Yubel". This card cannot be destroyed as a result of battle. When this face-up Attack Position card is attacked, inflict damage to your opponent's Life Points equal to the ATK strength of that monster. The controller of this card takes no Battle Damage from a battle involving this card. During each of your End Phases, destroy all monsters on the field except this card. When this card is removed from the field, you can Special Summon 1 "Yubel - Das Extreme Traurig Drache"" from your hand, Deck, or Graveyard.
Of course, you'll need this in the same deck. Note that if you use, say, Snipe Hunter to destroy your own Yubel, you still get to bring out this. Then you can nuke the whole field. Again, this sort of deck will need work.
PTDN-JP008
Yubel - Das Extreme Traurig Drache
The rest is unknown, but it has to be good.
PTDN-JP0??
Rainbow Dark Dragon
Light/Dragon-Effect/10/4,000/0
The rest is unknown. As far as we know, there are no plans to release the Advanced Gem Beasts.
PTDN-JP0??
Elemental Hero Storm Neos
Wind/Warrior/Fusion-Effect/9/3,000/2,500
Elemental Hero Neos + Neo-Spacian Aqua Dolphin + Neo-Spacian Air Hummingbird
The rest is unknown. If I were to guess, I'd say it would be close to its anime effect.
PTDN-JP018
Dark Nephthys
Dark/Winged Beast/8/2400/1600
When there are 3 or more DARK monsters in your Graveyard, you can remove 2 of them from play to send this card from your hand to the Graveyard. If this card is sent to the Graveyard in this way, this card can is Special Summoned from your Graveyard during your next Standby Phase. When this card is Special Summoned, destroy 1 Magic or Trap Card on the field.
A dark sister of the Sacred Phoenix, and not a bad card. Maybe has too high a price for a Monster with only 2,400 ATK, but still okay.
PTDN-JP0??
Dark Armed Dragon
Dark/Dragon/8/2800/1000
This card cannot be Normal Summoned or Set. This card can only be Special Summoned when there are only 3 DARK monsters in your Graveyard. Remove 1 DARK monster from your Graveyard from play to destroy 1 card on the field.
Powerful, yes, but way too hard to summon. If you have even one more than three Dark Monsters in your Graveyard, this would be dead weight. You want an Armed Dragon, go for the original.
PTDN-JP0??
Knight of the End
Dark/Warrior/4/1400/1200
When this card is Normal Summoned, Flip Summoned, or Special Summoned, you can select 1 DARK monster from your Deck and send it to the Graveyard.
Good lord, how long have they been hiding this guy?? This guy is wicked! You could use him to send Disk Commander or Dasher to the Graveyard... And so many other Monsters as well to retrieve later - all the Gravekeepers (combo with Rite of Spirit), all the Dark Scorpions (combo with The Warrior Returning Alive), DD Scout Plane, the Cyberdark Monsters (combo with Cyberdark Impact! and summon the big guy); this Warrior has SO many uses!
PTDN-JP???
Dark Burst
Normal Magic
Add 1 DARK monster with an ATK strength of 1500 or less from your Graveyard to your hand.
Another good card. Use to recover the card you sent to the Graveyard with Knight of the End!
That's all that's known for now, but this set looks okay for a start.