Normally, the Tier List is a reflection of what the best decks are within a tournament environment using Side Deck. However, such as with this occasion, sometimes the Tier List is a reflection of the TPC's opinion on the best decks for the 2nd Stage of the KC Cup.
A strong deck in the Meta Championship Series is likely also a strong deck in the KC Cup Stage 2. Although, there are some underlying factors that can make a deck better or worse for a KC Cup Stage 2 than it would be in a Side Deck tournament. For example, Cyber Dragon has the appeal of its duels usually being fast - allowing for the pilot to play a large number of games. And Thunder Dragon players have a much smaller chance of encountering direct counters like Loading... .
The KC Cup is here and with that we have a huge Tier List change. A lot of decks in this format get a chance to shine even though they are not well equipped to deal with a Bo3 side deck format. The reason why is simple. As long as you win more games, than you lose, your DP will increase and with that your Rank in the Cup as well. In a tournament losing twice in a match is game over in Top Cut, which is something nobody can afford. As such having a strategy which has a broken combo but only opens it up 60% of the time, is worth to consider. With that we introduce you Evil Eye, Lunalight, Triamid and Cydra back on the Tier List.
There isn't a lot to say about Onomat since we're so familiar with it by now. However, be aware of certain tech cards in Onomat such as adding Loading... into the Extra Deck to deal with untargetable cards like Loading... . Additionally, there is some flexibility in main deck's tech space to add things like Loading... , Loading... or more Loading... s (based on the tendencies of the ladder}. Backrow removal is also fluid, as this deck can comfortably use Loading... , Loading... or Loading... depending on what the other techs are dealing with.
Onomat remains Tier 1 even in a non-Side Deck format. Thanks to its fast OTK power and a stable Turn 1 board with either a Loading... protected by backrow or a Loading... that gives you hand advantage for follow-up plays. In addition, Onomat can quickly adapt to the small meta shifts in the KCC through your big selection of Xyz monsters.
Cyber Dragons are back like they always are for KC Cup season due to the nature of the deck and the format. This is one of the few decks in the game that can easily OTK through almost any board, provided they open Loading... and Loading... or Loading... . The deck naturally beats backrow and slower control strategies as not being able to instantly pressure Cyber Dragons can lead to your field being opened up by Loading... or multiple Loading... s with the help of Fusion Gate and Loading... . The threat of having to play around Cyber Style to avoid giving the Cyber Dragon player Loading... s and potential Fusion or Overflow plays, along with the threat of Loading... being set can buy them extra turns as the opposing player doesn't want to attack to open their field up for an OTK. It also doesn't help that not attacking allows cards like Loading... and Loading... to stay live, which can trigger the skill anyway and remove threats from the opponent’s board.
The consistency in opening these hands with enough tech cards like Cosmic Cyclone, Loading... , Drowning Mirror Force, and / or Herald of the Abyss to make OTKing / surviving more practical is one of the weaknesses of the deck. However in the KC Cup, where you can play as many games as you want in a 3-day period, Cyber Dragons can brute force their way into having success, as the deck is fast enough to play 800+ games and have these bricks be overshadowed. This deck getting multiple Top 100s / Top 10s is standard for the KC Cup and that still hasn’t changed for all the formats it’s been in due to it being able to brute force success with the primary help of the Loading... + Cyber Style combination. It also helps that counters to other strategies, like Evil Eye, Triamid, and Lunalight, lose to Cyber Dragons, because of the deck's natural ability to run through both backrow and untargetable Monsters. To put it simply, you win fast and lose fast playing this deck and that’s a viable strategy in the KC Cup.