Bonus/Secret Report

So, I hope you enjoyed this short adventure of Riku Replica. There are a couple of details that haven't found place in the story, and I would like to share them with you.

First of all, maybe you've noticed, but in my mind Repliku's return happened by the form of a Lingering Will. Just like Terra in BbS, he didn't have a body, only a vessel to contain his mind. His ghostly appearance is, of course, a creative freedom I took to tell the story. His helmet, an homage from Master Xehanort, is the same (or a very similar one) of Vanitas.
Next, I made a specific timeline to fit the events of the fic with the ones of the videogames, starting from the one showed in the "Kingdom Hearts 358/2 Days Ultimania". In italic, the events seen in Chain of Memories and Days, in bold the ones depicted in this story.

DAY 49: Sora defeats Marluxia and go to sleep
DAY 51: Riku defeats Riku Replica
DAY 52: Riku and King Mickey leaves Castle Oblivion
DAY 68: Riku Replica returns with King Shadow's help, he meet Naminé and DiZ [chapters 1-3]
DAY 70: Riku Replica meets Pete and Axel [chapters 4-6]
DAY 71: Axel returns to the World that Never Was
DAY 72: Roxas and Axel tails Pete in Agrabah
DAY 74: Xion loses her ability to use the Keyblade
DAY 75: Roxas and Xion fights Pete in Agrabah
DAY 91: Riku and Mickey visits Hollow Bastion, Riku Replica and Naminé visits Twilight Town. Riku Replica defeats Pete in the Old Mansion [chapters 7-8]
DAY 92: Riku Replica defeats King Shadow [chapter 9]
DAY 95: DiZ and Naminé moves to Twilight Town
DAY 96: Xion can use the Keyblade again, causing a disturbance in the process of recovery of Sora's memories [chapter 10]

Also, I'm pretty sure you've noticed, but the report that Riku Replica finds out in Vexen's lab, is the same (and the only one) written by Vexen in 358/2 Days.
"The Program is largely on target. No. i, my finest Replica, has proven an even greater success than anticipated. I intend to take the other vessel - judged unfit for number status - to Castle Oblivion, where I will subject it to further testing. One thing is clear: could these Replicas not be classified as a special sort of Nobody?"

Last but not least, maybe you've wondered why I chose the puppet with number 17 to make Riku Replica return during the final battle.
Well, there are a lot of meanings for this number. In the cabala is a positive number: "1" is the number for God and "7" is the number of knowledge. If added we get an "8", that if overturned becomes the infinite symbol. Also, the "8" in tarot represents the balance between God and men.
Also, there is a negative meaning. In latin is written "XVII", which anagrammed is "vixi", latin for "I lived", so… I'm dead!
Plus, remember what DiZ said about a possible Riku Replica's return, well… who knows? Maybe in Kingdom Hearts 3? I really hope so.
Also, according to the timeline above, Riku Replica is defeated by Riku during Day 51, and returns on Day 68… exactly 17 days later.

In order to close, the last words Riku Replica said before vanish in Naminé's hands, are the same he said after being defeated by Riku in Re:Chain of Memories.