The manga had two volumes and was followed up by a sequel, Mobile Suit Gundam Day After Tomorrow - Kai Shiden´s Memory, which ran from April 2009 to November 2012. This one however fast-forwards to UC 0105, as an older Kai is invited to speak in a OYW memorial exhibition that's about to be opened in Zum City. His recollections of his time onboard White Base and afterwards however reveal a bit more than just memories.
This manga provides examples of the following:
- Adaptation Expansion: The manga expands upon some scenes from the show involving Kai, such as his brush with Reccoa and his meeting with Sayla.
- Badass in a Nice Suit: Kai is almost always shown wearing a sharp suit, even in the jungle.
- Badass Normal: In addition to having kicked ass alongside Amuro in the OYW and barring the baseline Newtype awareness that the rest of the White Base crew developed, he proves that he doesn't need a mobile suit to be a badass.
- Been There, Shaped History:
- In addition to his adventures as seen in Mobile Suit Zeta Gundam and Mobile Suit Gundam Unicorn, he's shown to have stumbled onto various events, at times with more lasting repercussions. A particularly heated argument with Hayato over the growing corruption and conspiracies within The Federation led to the latter joining Karaba and ultimately calling the shots there.
- It's also implied that he was in Dakar when Quattro's speech before the Earth Federation authorities was taking speech. And helped guarantee in secret Beltorchika's passage into the assembly building.
- Bystander Syndrome: Prior to his time in Karaba, Hayato attempted this, in part to keep his family safe and out of the belief that his war's over, despite being aware of the Federation's festering corruption.
- Character Development: Kai noticeably changes over the course of time since his days on White Base, though some things remain constant.
- Continuity Nod: Several characters and events from different UC works either show up or are referenced in some manner. In addition, Kai's Memory takes place in UC 0105, around the same timeframe as Hathaway's Flash.
- His interview with a former aide of Dozle Zabi who's posing as an astronomer ties in to Char's Deleted Affair as he learns of Haman Khan's Start of Darkness and her true intentions.
- Deadpan Snarker: Even decades later, he still has it.
- Death Seeker: Some of his riskier adventures, including one where he gets beaten up by the Titans suggest this. Which could be out of guilt for not saving Miharu.
- Defector from Decadence: Kai seems to see himself as this, though he doesn't disparage the likes of Bright or Amuro for still serving the Earth Federation.
- Dented Iron: Downplayed for the most part. But while he develops into a veritable badass in his own right, his painful trauma from the OYW keep him from ever piloting a mobile suit again. Not to mention that he remains haunted by Miharu's death, even several years later.
- Face of a Thug: No matter what era he's in, he still has this.
- Famed In-Story: By the time Kai's Memory takes place, he's long considered this by others in the Earth Federation. On the other hand, it helps as well that by then, he's among the few remaining White Base veterans known to be alive, including Bright.
- Former Regime Personnel: Kai encounters his share of these in his investigations. With one in particular being a former aide to Dozle Zabi who tries burying his Zeon past under the guise of an astronomer.
- Gilded Cage: The manga also goes quite a bit into how the other White Base veterans are either this (as with Amuro) or otherwise marginalized by the Earth Federation.
- Government Conspiracy: The more Kai delves into the dark recesses of the Earth Federation, the more damning secrets he uncovers. The Titans are just one example.
- Hero of Another Story: Compared to Zeta, where Kai's off-screen exploits were largely hinted at, here much of said exploits are in full view.
- Intrepid Reporter: Kai, with a dash of James Bond in for good measure.
- Jerk with a Heart of Gold: It's shown that he can as rude as much as he can be charming. Still, he's a good man at heart.
- Oh, Crap!: Despite being captured by the Titans at one point, Kai gets one upon finding out that the aircraft carrier they're on is being attacked by Zeon remnants.
- Really Gets Around: It's strongly implied that Kai Shiden became quite the ladies' man and casanova, which both Frau and Sayla lampshade. Nonetheless, he still longs for Miharu.
- Shell-Shocked Veteran: Kai manages to get by better than Amuro in this respect, but he still has moments when his trauma gets the better of him. At one point, he suffers a mental breakdown as memories of the One Year War and his time with Miharu are triggered.
- Slice of Life: Some of the vignettes follow Kai's everyday life, or rather what passes for it given his line of work in the Universal Century.
- Took a Level in Badass: Over the course of the flashbacks, he visibly does.
- What the Hell, Hero?: Kai calls out the likes of Hayato and Quattro aka, Char Aznable, whether for standing by while The Federation slowly succumbs to its hubris and corruption, or for living a lie.
