Alright so I watched the Decade Finale RAW, and I'm going to put down what I'm pretty sure was said and what I got from it as well. MAJOR SPOILERS, DO NOT READ IF YOU DON'T WANT TO BE SPOILED WITH THE FINALE, OR WITH BOTH MOVIES.
[HIDE]So, basically we get the brawl with Super Apollo Geist and the big bads from each main Rider world visited (minus Gyuki and the big bad in Kuuga world for some reason, and Ryuki had no big bad). The combined forces of Decade, Diend, AU Kuuga, AU Kiva, and AU Hibiki destroy the big bads with probably one of the lamest sets of Rider Kicks I've ever seen. Within those Rider Kicks, Diend's legs shoot out cyan flames, AU Kuuga's shoot out flames, AU Kiva doesn't do Wake Up so it's a normal kick as is AU Hibiki. Decade Complete actually apparently uses a card because we hear "FINAL ATTACK RIDE: D-D-D-Decade!" but it doesn't look anywhere near as epic as it should, nor as epic as it does in the Climax Heroes video game. Super Apollo Geist uses Super Geist Cutter aka Captain America ripoff move towards Decade Complete, but AU Kuuga gets in the way, getting knocked unconscious and out of his transformation. Decade Complete uses FINAL ATTACK RIDE: DIEND that Diend just randomly tossed to him (by the way, it wasn't the Final Attack Ride card shown, it was Diend's henshin card, once again showing that Toei has no attention to detail) for them to do the finisher together on Apollo Geist, which is what makes all the cards on Decade's chest switch over to Diend. They blows up Apollo Geist. Everyone's happy yay! Except Natsumi realizes that they are in the very same spot and she is in the very same dress that was in her dream from the ep 1 intro. OH SHI-! AU Kiva and AU Hibiki disappear like AU Blade did! OH SHI- again! Then, suddenly, Tsukasa turns around and he's back where he was in ep 1 when he was speaking with Kurenai Wataru, and there is the half Fangire himself. He proceeds to tell Tsukasa that he failed in saving the world, or that he is the real threat or something. I specifically hear him say something about being the Kamen Rider who destroys everything ("Anata subete Kamen Rider hakaisha something something"). And then I think he says something about him and his comrades now having to deal with Tsukasa. He transforms (with no animation of Kivat

), and we even get to hear the cry of Kiva Flight Mode with the delayed eye-shine. He charges at Tsukasa, and then suddenly Tsukasa is back in the world of the Rider War, surrounded by what can be assumed to be all the ORIGINAL Riders, sans Kuuga. Kenzaki Kazuma arrives with a simple and casual "Decade-o, omae wa taosu..." which in English of course means "Decade, you will die..." followed by "Henshin..." again very casual into King Form. Tsukasa Henshins. Natsumi is like "Oh noes... WAIT, YUUSUKE IS STILL HERE AND NOT MOVING!" and proceeds to run to Yuusuke. Kivala shows up, is all like "Bitch, move," GABU-bites Yuusuke, you actually see the Active Force go into him from the bite. She announces the arrival of Ultimate Kuuga. Yuusuke then shoves Natsumi out of the way, stands up, looks all crazy like, and transforms into Black-Eyed Ultimate Kuuga, while Kivala cackles like a witch. Narutaki fangasms over all the Kamen Riders arriving to finally kill Decade. RIDER CHARGE! Diend arrives! Is Decade getting help? "Tsukasa..." "Kaito?!" BLAM! NO! DIEND SHOOTS HIM POINT BLANK IN THE FACE! Natsumi then shouts out "DECADE-O!" and end episode. Fucking cliff hanger. Also, why would Natsumi shout out "Decade" and not "Tsukasa"? This is from what I can recall the first and only time she does this. Then we get the movie teasers.
In the teasers, you clearly hear Natsumi say "I will kill/defeat Decade!" as she hoists up the shot gun. What?! Then Kamen Rider Kivala arrives, announces herself as Kivala in Kivala's voice (wtf?) and bitch-slaps Decade Complete. We then see a black-haired, black-clothed Tsukasa punch a lighter-haired Tsukasa wearing what looks like Doctor Who clothes, then become Decade Complete to beat up Doctor-Tsukasa some more. We also see Kuuga casually **** up Diend. Then, a mysterious person in white with floofed back hair appears. End teasers.
I have to say, the finale was insane, but could've been handled much better. From the teasers, I like what I see, except Kivala. I'm sick of seeing secondary Kiva riders WITH THE SAME DAMN COLOR SCHEME. IXA, Rey, and Saga all had the white-and-blue color scheme. COME UP WITH SOMETHING NEW TOEI! I would've loved to have seen something similar to this pic

Also, Kivala is too small to be on a belt. She should be like a Henshin Brace instead.
What I get from this episode, with Narutaki always saying that Decade is in fact destroying worlds, and Wataru telling him he failed... is that Decade really was supposed to destroy the worlds he visited. I think they were some kind of false worlds that were interfering with and destroying the true Rider Worlds, and by helping them exist, Tsukasa did in fact screw things up and allowed Dai-Shocker to screw things up even more. We already get that from the symbols and from the movie, that Tsukasa came from the world of Dai-Shocker, and in fact worked for them and that Decade was made by Dai-Shocker. So Decade screwed up, and now truly the only way left to fix things is to kill him. Woops. So we'll find out how things end in December then.
Also, this episode I believe proves that the movie is officially an alternate ending. God dammit.[/HIDE]