Why doesn't Gintoki tell his story to Shinpachi, Kagura and the audience with his own words? Why does he always send them away in battles? Why does he always hide his back that's covered in scars? He doesn't want to drag them into his bloody past and see that he's a murderer (unwilling yes but still).
Of course Elizabeth is a royal, It comes with the stereotypically royal name! He even shares his birthday with one of the Queens bearing the name!
Apperances can be decieving is a common theme. Angelic Blu-Rayko is like a grim reaper, doing everything to kill Gintoki in her power. While the grim reaper esque Asaemon is coming to judge him but like an angel gives him a chance to make up for his sins and get forgiveness. This was in fact foreshadowed early on with Kagura entering sadist mode in an angel costume and usually Nice GirlHeidi dragging him to hell.
Nobume's name is a Meaningful Name. Both ways. Her original name under the Naraku was "Mukuro", which meant "corpse", describing her only purpose in life if she only served them: bringing death and being punished by it if she failed them (basically, she was only a tool). Nobume, 信女, has the kanji for "confidence/belief/faith" and "woman". Now, considering that some years after her first appearance, it was revealed that this was the name that Isaburo thought for his newborn daughter, and that he baptized Mukuro as "Nobume", it does show what kind of person Nobume turned up to be, instead: that he believed that she wasn't a mere tool but a human that at the end changed her own destiny under his wing.
Even if his injuries are Played for Laughs, Shigeshige is ridiculously Made of Iron for someone who's supposed to be little more than a puppet figurehead. Then we find out that as a young boy, Shigeshige switched places with his ninja body double, and that he went through a Training from Hell under the Oniwabanshuu.
Mutsu's name makes sense in hindsight, given that Sakamoto Ryouma's favorite sword was the Mutsunokami. The reason why she's so adept in physical combat and is capable of leading the Kihetai is because she's Tatsuma's metaphorical sword instead of his literal one. It's also the name of an actual diplomat, Mutsu Munemitsu—who was one of the real-life Ryoma's most competent administrator/co-member in the Kaientai.
What would've happened to Gintoki's psyche if Abuto had killed Kagura and Shinpachi..? Too horrifying to imagine...
More like Fridge Ouch but oh well. In the Yoshiwara Arc when Kagura and Shinpachi fight Abuto is Shipachi hit so hard in his stomach that he starts bleeding internally. When that on it's own might hurt like hell, does he drag Kagura away from killing Abuto. Keep in mind, Kagura is heavy as lead, making it even more painful... Ripping his insides... Probably...
The entire Shinigami arc when one know what happened before Gin-chan was sent there.
Both Gin-chan and Hijikata are horrified of ghosts, and even though it's mostly Played for Laughs, one has to remember that Gin-chan grew up on the battlefield, and that Hijikata went on a killing spree before he befriended the Shinsengumi. They are probably afraid to be visited by those ghosts, the ghosts of their pasts.
It goes a hundred times scarier for Gintoki when you consider that before he was forced to kill Shouyo in front of Takasugi and Katsura, he also witnessed many of his comrades falling to their death during the Joui War. He feels guilty that he couldn't protect them all, and his nightmares sometimes feature this fright as well. During the Farewell, Shinsengumi arc, when he unmasks Utsuro, he finds out that his fighting skills and physical looks are similar to Shouyo'snote it's later revealed Shouyo is a personality/identity Utsuro assumed when he "dissapeared". It raises some flags as well if you consider that, that is his living nightmare: as if his mentor and father figure was brought up from beyond the grave just to punish him.
Also for Hijikata, he made dozens of men commit Seppuku at a slight suspecion of treachery. The real deal also made his best friend do it. Including to his dead brother whom tried to save him. Now, imagine fearing the only person to ever truly accept you to judge and hate you...
More Fridge Hurt than horror but in the Red Spider Arc notice the shocked expression on Gintoki's face when Tsukuyo finished off her own master, a person that in Gintoki's own words she looked up to and wanted to be like, at that point you think he's just surprised but come Chapter 521 and one can only imagine the pain of the memories rushing back to him.
Gintoki drinks a lot. It's usually played for laughs, like sticking his head in a vending machine or when a bunch of Kabukicho's women pranked him to get him to ease up on the sauce. But with a past like his...
The twist of the Shogun Assassination Arc is that Hattori didn't kill the Shogun, he killed his double. But the Shogun's doubles were all fellow Oniwaban, and a few were his friends. Even if it wasn't the Shogun, he was forced to kill one of his friends for a ploy.
In the anime, the first episode of Gintama. had the Odd Jobs characters pick up one of Kusuo Saiki's Power Limiters when they move back into their old timeslot. Considering how much raw, uncontrolled power he has without one of them on in his home series, just what did Saiki accidentally do to leave the void Gintoki and the gang walked into?
In Kagura's death arc, Okita said that Gin and Shinpachi would realize that Kagura's alive if they love her. And yet, he's the first to find out. Is that a love confession? Granted, it could be love as friend or family, but still.
Utsuro's goal is to die, but he's immortal. But the source of his immortality is earth's energy. Why can't he just take a hike to another planet and live out his life there? Then again, hardly anyone knows how an immortal like him can die...
In the Scandal arc, despite Gintoki getting set up with a harem that includes Tsukoyo and Tae, there is no sign of complaint from Shinpachi and Kondo and Hinowa (their closest relatives, and stalker). This is a clear tipoff that the harem is a setup, because no way would any of those three, especially Kondo, be okay with letting an unpredictable bum like Gintoki be with their lady. They must have been warned beforehand so that they wouldnt interfere.