There was no clear connection between Sanguine Red's novels," Tengen " and " Tengen 1 ", which could form an independent series. However, judging from the name, Tengen could be considered a follow-up to Tengen 1 because Tengen was usually used to refer to the first work in the series. However, this was not absolute, because the name connection did not necessarily mean that there was a direct causality between the works.
If Hidan were to be captured and tortured, Kakuzu would be enraged. After rescuing Hidan, Kakuzu would stay by his side during his recovery. He'd be uncharacteristically gentle, making sure Hidan had food and water. Hidan would be touched by this side of Kakuzu that he rarely sees, and it would strengthen their relationship.
One great 'Harry x Sirius Comfort' fanfic is 'A Shoulder to Lean On'. It beautifully portrays Sirius being there for Harry during a tough time at Hogwarts. The author does an amazing job of showing their bond through simple yet powerful interactions.