- In the anime, it seems possible that Gungrave takes place in the future of Trigun, since Big Daddy told Brandon that the city used to be a desert, like the world of Trigun, plus the overall technology is more advanced than that of Trigun. The presence of the racing animals also implies that it's the same world.
- Jossed: Trigun's world has two suns. Gungrave's world only has one. Furthermore, Gungrave's world has several massive bodies of water that wouldn't be able to exist on Planet Gunsmoke due to the presence of the aforementioned two suns.
- Realistically speaking, Gungrave's lore was written around the same time Trigun was JUST transitioning into Trigun Maximum. A lot of the stuff that was featured in Gungrave can be directly compared to things later (or earlier) appearing in Trigun Maximum. (SEED vs the Plants, Brandon and Bunji's character development as partners/eventual rivals vs Wolfwood and Vash's, Billy and Kabane vs Vash and Wolfwood, Fangoram vs Razlo, Grave and Fangoram's weapons in comparison to Wolfwood's Cross Punisher, Mika Asagi vs Meryl Stryfe, etc.) It's more likely that Gungrave was Nightow's means of testing concepts he would later use in Trigun Maximum. (Along with tweaking ones he'd used already.)
The main character of Kazuma Kiryu is a spectacular fighter who quickly rises up through the ranks of a mob family, until that is ground to a screeching halt because of his loyalty to his best friend who has killed someone (... in Brandon's case he is the one who is killed, in Kazuma's it's someone else that Brandon takes the heat for it). They are both, despite their professions, absurdly nice men.
When both of them return (stronger than ever), they both wind up protecting the daughter of their love interest, who after their relationship couldn't work, went on to be involved with a very powerful man and have his child. In the end they wind up fighting their old friend but, at the last minute, they reconcile somewhat (though the friend still dies).
It's from Brandon/Grave's point-of-view, so he becomes the Audience Surrogate: You're seeing everything through his eyes. Brandon's defining feature is how he places others before himself, and his lack of self-interest is what puts so much of the spotlight, and subsequent development, on other characters. The ones Brandon has more invested in, as a result, get more development and screen-time because Brandon affords them more personal regard.
- There are some subtleties that hint Grave's survival. What is the title of the theme that plays in the background during the finale? Happy Ending. It starts playing when Mika begins speaking about 'family'. But why is she shocked and gives out a Tearful Smile instead of running towards Brandon/Grave like usual? At that moment, Brandon/Grave condition is far more terrible than the last time she sees him before he leaves; he has lost an arm, a leg, and his face is also cracked.
- When the screen goes black right after Maria calls out Brandon's name, it's followed with Mika's voice calling out Brandon's name before the flashback between Brandon and Harry start. After the flashback, we can also hear Mika say, "Okaerinasai/Welcome back/Welcome home." It's likely that the characters calling out Brandon's and Harry's names are playing in Brandon's memory along with the flashback. It can be assumed that Grave survives and is perhaps unconscious and/or put in hibernation, and he may now be under the care of Millennion scientists and Mika. It is possible because Biscoe, the current leader of Millennion, respects Mika as she is Big Daddy's child, so Mika may have some authority.
- Also, Biscoe has re-hired those who once worked for Laguna Glock to produce Anti-Necrolyze bullets. Sure, the research facility is destroyed, but one can't create those bullets and explain how they work (to the point Biscoe asks to 'spare the advertising') without knowing the basics of Necrolyzation technology, especially how Necrolyzers'/Orgmen's/Deadmen's bodies work.
- In addition, Dr. T estimates that Grave can still move for about ten days after the last treatment. Ten days don't seem to have passed since Dr. T's death in episode 22 (episode 23 to 26 happen in a very short span of time, especially after 24).
- Dr. T's trailer is still seen in episode 23 too.
- Additionally, Grave's pistol (which Harry uses to shoot him during their attempt for Mutual Kill) has no bullets. It's shown during the moment when Harry has just been shot for the first time, in which Grave pulls the trigger of his old gun. There's just a click, nothing else.
- The definition of family and why Mika gives out the family speech in the finale. In episode 21, Mika learns from Gary and Widge that family means something like 'never betraying each other.' In episode 22, realizing that Brandon/Grave is fighting to protect her, she wonders if she and Grave are a family. In episode 24, after Grave agrees that they are a family, Mika immediately hugs him and says, "Then I'll have faith. That you'll come back." The definition of family in Mika's mind is 'never betraying each other,' which is why she reacts that way. When she discovers that Grave's body is falling apart, she outright says that she's afraid that Grave can't come back. In the finale, after finding Brandon/Grave, she gives out a Tearful Smile and says that she and Brandon/Grave are a family forever. This may mean that Brandon actually comes back to her. And when the screen goes black, we hear her say, "Okaerinasai/Welcome back/Welcome home."
- Biscoe suddenly snaps at his men to stop the attack.Biscoe: That's right. I'm telling you to stop the attack. *pauses, then suddenly grows angry* You idiot! Get in touch with them immediately! Right away!
- Biscoe, Norton, and Mika are going to find Brandon/Grave, but if Biscoe's men know that their superiors are coming, they aren't going to be that rebellious (implied by Biscoe's sudden anger). It's more likely that Biscoe tries to save Brandon (see the point regarding the re-hired scientists), but his men don't really agree.
- Speaking of rebellious, when Biscoe orders his men to stop the attack, Harry has been shot down.
- Also, when Necrolyzers/Deadmen die, they are dust. Mika can't determine if Brandon is at peace/Go Out with a Smile when he dies.