Short answers, pulled from the story.
Yoshitaka Murayama stood at the helm of a new project in 1995 when he began shaping what would become the Suikoden series. He drew his core inspiration from the classical Chinese novel Water Margin known as Suikoden in Japanese.
The 27 True Runes exist as sentient sources of magic and primal forces throughout the fictional universe. These entities grant immortality to those who bear them yet also bring negative consequences such as transformation into vampires.
The Northern Continent holds the Scarlet Moon Empire with its capital city Gregminister situated in Arlus. North-west of this empire lies the Dunan region which splits into the Highland Kingdom and Jowston City-States before unifying into the Republic.
Yoshitaka Murayama directed Eiyuden Chronicle: Hundred Heroes which released on the 23rd of April 2024 before he passed away during its development. The creative team included Junko Kawano and composers Motoi Sakuraba alongside Michiko Naruke.
On March 3rd and 4th, 2025 Konami announced through livestream they were working with Mythril on a new gacha game spinoff titled Suikoden: Star Leap. This project is set chronologically between Suikoden I and V and remains completely canonical to the mainline continuity.