Quite a fair amount of the cast is different from the original story so this is devoted to reminding us how they were and explaining how they are different.
The New Digidestined
Takeru "TK" Takaishi
One of the eight Digidestined from Digimon Adventure, TK's no longer the kid he used to be. He now lives in a changing world and must deal with growing into adulthood while fighting the darkness from his past, all the while serving as the leader to a new group of Digidestined
Hikari "Kari" Yagami
One of the eight Digidestined from Digimon Adventure, Kari is still as sweet as she was back when she was eight. That sweetness though hides a steely determination and she's not afraid to fight to defend her friends. However, her mysterious powers tied to her Crest of Light may yet prove to be more dangerous than helpful, when a force more sinister than anything seen before claws its way out of the darkness in search of her.
Daisuke "Davis" Motomiya
A passionate classmate of TK and Kari's, Davis can be a little foul-mouthed, brash and arrogant at times, but he's as solid a friend as they come. Energetic and confrontational, he's not going to just sit back while his friends risk their necks, for better or worse.
Miyako "Yolei" Inoue
Izzy's protégé in computers, she's more a gamer than a programmer. Despite her flaky personality and poor hygeine, she's eager to help the others defend the Digital World, but years of hiding her frustrations in video games have left her ill-prepared for what adventures the Digital World may bring.
Iori "Cody" Hida
The most mature of the three new kids, Cody takes a lot of things with a grain of salt and tries to err on the side of caution. That said, he is also set in his beliefs and is determined to always do the right thing, though his unmovable black and white view of the world can often work against himself and the other Digidestined.
A child prodigy who somehow found his way into the Digital World, and has made it his life ambition to enslave its monster populace. Cold, calculating and out for blood, there are deeper secrets to his arrival in the Digital World than even he is aware of, which will ultimately threaten his rule and turn his life upside down.
The Original Digidestined
Taichi "Tai" Yagami
The de facto leader of the original Digidestined , Tai finds himself placing his faith in the newer group of Digidestined, regardless of how much he'd rather handle things himself. His years since the first adventure have mellowed his hotheaded personality, though he remains as oblivious to everything in front of him as ever. Even on the sidelines, the new forces at work will cause Tai to face new challenges in both the Digital World, and the real world.
Yamato "Matt" Ishida
Tai's best friend and the loner of the original Digidestined, Matt is outspokenly uncomfortable with the new Digidestined, causing him to feel as though he's been replaced. Trying to build a musical career, he struggles to find footing as a Blues musician in a world of Rock n' Roll, especially when his biggest fan is his worst nightmare. Despite his discomfort and disaproval, Matt can still be depended on when needed, though you can bet he'll be scowling the whole way.
Koushiro "Izzy" Izumi
The brains of the original Digidestined, Izzy is by far the most involved with the new children, acting as a guide and general backup when possible. Though unable to enter the Digital World without aid, he spends most of his time buried in his computer, keeping an active eye on the strange developments in the Digital Frontier since his last visit. While he has become far more personable since first entering the Digital World years ago, this new adversary threatens to tear his entire world asunder, in more ways than he could possibly imagine.
Sora TakenouchiThe heart of the original Digidestined, Sora finds herself at odds with the sudden re-emergence of the Digital World in her life. Though she wants to believe the new children are capable of handling themselves, she struggles to hide her doubts as to wether or not they can pull it off. Additionally, her tomboyish personality is beginning to conflict with her femininity, often leaving her confused and unsure of what to do. She puts it upon herself to act as a guide to Yolei in both life and Digital World matters, although she'll end up facing more personal demons than she bargained for in doing so.
The passion of the original Digidestined, Mimi has made a strong effort to distance herself from her old friends in the time since their original adventure. What had initially been a humbling journey of self-discovery has since soured into a debilitating case of PTSD, causing her to do whatever it takes to avoid returning to the Digital World. Despite her coldness, she is still outwardly concerned about her old Digimon partner, Palmon, so there may yet be some trace of the old Mimi left.
The medic and rational mind of the original Digidestined, Joe finds himself frequently unable to rejoin his friends due to spending most of his time in college. When he can afford the time to join the others, he frequently finds himself acting as a mentor to the young Cody, trying his best to guide his new young teammate along. He is also trying his best to convince Mimi to rejoin them in their efforts to free the Digital World, a task that only seems to grow more and more difficult with each attempt.
The original Digimon partners
The emergence of the Digimon Emperor has lead to a large scale enslavement of the Digital World's inhabitants, including the Digimon partners of the original Digidestined; the happy go-lucky Agumon, the shy Gabumon, the whimsical Tentomon, the motherly Biyomon, the cheery Palmon and the easygoing Gomamon. Without their human partners to assist them, the Digimon have since become slaves to the Emperor, forced by the power of his Dark Rings to act as his personal Generals. The first challenge of the new Digidestined will be to free the Digimon partners of their predecessors, which will certainly be easier said than done.
T.K's Digimon partner. As he was able to escape the Digimon Emperor's enslavement, Patamon has since rejoined his long lost partner. Due to his inability to become Angemon thanks to the Emperor's Control Spires, Patamon has since adopted the Armor Digivolution of Pegasusmon after discovering the mysterious Digi-Egg of Hope. While this has largely robbed Patamon of his original power, he is nonetheless happy to be back by T.K.'s side, eager to help retake his world from this mysterious new Emperor.
Kari's Digimon partner and former servant of Myotismon. Gatomon barely managed to escape the Emperor's enslavement, though it ended up costing her her tail ring and a large portion of her power. Unable to become Angewomon even after rejoining with Kari, Gatomon is able to adapt the form of Nefertimon using the mysterious Digi-Egg of Light. By far the most mature of the Digimon partners, Gatomon finds herself in a strange, constantly changing new Digital World, and is determined to make sure Kari remains safe from something even worse lurking in the shadows.
Davis' Digimon partner. This mysterious, supposidely mythical dragon Digimon appeared in the nick of time to save its newest hero. Perpetually happy and stuck with a prominent lisp, Veemon is eager to help his new friend retake the Digital World from the Digimon Emperor, but finds himself ill-prepared for yet utterly fascinated by the human world, especially its cuisine. Veemon also develops a close relationship with Davis' sister, much to his partner's annoyance.
Yolei's Digimon partner. Hawkmon finds himself the odd man out, being a male digimon with a female partner, let alone one as strange as Yolei. The humble bird Digimon often finds himself deeply confused by his partner's antics, and often tries to act as her conscience and voice or reason, usually to failure. Despite the friction between the two, Hawkmon is a loyal Digimon dedicated to helping his partner whenever possible, no matter how questionable it may seem.
Cody's Digimon partner. This voracious armadillo digimon speaks with a southern-drawl, and acts as the more relaxed contrast to his disciplined partner. Though he tends to think with his stomach more than his head, Armadillomon is a true friend, and does his best to help Cody cope with a world he doesn't understand.
Ken's Digimon Partner. This insectoid Digimon has long since found himself acting as the Digimon Emperor's servant rather than his partner. Though he finds himself unable to dedicate himself to Ken's cause, he will nonetheless fight tooth and nail to defend his partner when threatened. Perpetually abused and sheepish, Wormmon constantly attempts to persuade Ken to return to his old kind self, though his efforts have done nothing but infuriate the Digimon Emperor.
Davis' older sister and Matt's "biggest fan". Impulsive, headstrong and just as loud as her younger brother, once she has set her mind to something, Jun is not easily swayed from her path. Generally dismissive of Davis' weirdness, she has nonetheless latched onto his new "doll", unaware it is in fact a living creature. Her infatuation with Matt also causes her to constantly show up in the Digidestined's lives, for better or worse. Although the Digidestined fear her snooping ways will eventually lead her to the truth of their adventures and thus put her in danger, they may be surprised to learn their concern should be for those who end up on her bad side.