The Complete Timeline of That Time I Got Reincarnated as a Slime – Explained (2026 Guide)

Credit:- 8-Bit

It’s no secret that the That Time I Got Reincarnated as a Slime or TenSura series has one of the most complex timelines in all of anime and light novel history. That said, the anime briefly mentions the past, but nothing is really laid out as a definite timeline explanation.

And that is the very reason we did the research and analysis, so you don’t have to. Here is the complete timeline of That Time I Got Reincarnated as a Slime, from the beginning of creation to the post-story era.

1 The Era of Genesis and Ancient History

Veldanava in That Time I Got Reincarnated as a Slime | Credits: Shosetsuka ni Naro & Kodansha

The world of That Time I Got Reincarnated as a Slime begins with Veldanava, the first True Dragon, also known as the Star King Dragon – one of the strongest characters of the universe. While the exact date of the world’s creation remains a mystery, Veldanava gave life to fundamental entities before the separation of heaven and earth and the existence of matter.

While the 7 Primordial Angels (aka Seraphim) were born from the great Holy Spirit of Light, and from the great Holy Spirit of Darkness, the 7 Primordial Daemons were born – Guy Crimson, Testarossa, Diablo, Misery, Carrera, Ultima, and Rain. Feldway was among the first of the Seraphim, who we know today as the Phantom King.

After Veldanava created the world and his desire for companionship was fulfilled, he wanted to create a civilization by creating the Divine Ancestor, Twilight Valentine. Twilight then analyzed his own body and gave birth to the High Humans and the Vampires. Meanwhile, Veldanava brought two other beings into existence – Ramiris and Dagruel. However, in her current state, Ramiris has completely forgotten about her origin.

Ramiris from That Time I Got Reincarnated as a Slime | Credits: 8-bit

On the other hand, Dagruel has two brothers – Fenn and Grasword. During the mythical era, the brothers fused to form the God of Destruction, Ashura. Ashura spread chaos across the land and even dared to challenge Veldanava himself, but was defeated and sealed away. After their defeat, Dagruel and Grasword swore allegiance to Veldanava, but Fenn kept up the revolt. Dagruel was then entrusted with guarding the staircase leading to the Palace of the Celestial Stars.

To make sure monsters like Ashura were sealed, Veldanava created the sacred sealing chain, Gleipnir. Meanwhile, the 7 Primordial Daemons showed no interest in the creation of the world and took residence in the World of the Underworld. Diablo and Guy Crimson clashed in a battle of supremacy, which ended in a draw. Even Rain and Misery tried to challenge Guy Crimson, but both were defeated. While the Daemons kept fighting among themselves, Veldanava’s dream of diversity came true thanks to Twilight Valentine.

Twilight gave birth to several lineages from different elements: the High Dwarves (Earth), Mermaids (Water), Enki (Fire), and the High Elves (Wind). However, Twilight went into a creation madness and experimented on the current being, creating new species: the successful ones were the Ogres, Elves, Dwarves, and Lycanthropes; among the failures were the Goblins and other malformed creatures.

Following the narratives of the True Dragons, we learn that a massive dispute broke out between the dragon sisters Velzard and Velgrynd regarding the upbringing of the child, Veldora. As Chronoa, a manas born from the memories and emotions of Chloe Aubert, seals Veldora, Guy Crimson becomes a Demon Lord, bringing us to another timeline of the story.

2 Shizu Era (Pre-Rimuru Timeline)

Shizu from That Time I Got Reincarnated as a Slime | Credits: 8-bit

During the bombing of Japan during World War II, Shizu was summoned into the TenSura world by the Demon Lord, Leon Cromwell. She was badly burnt from the bombing, and Leon saw her as nothing more than a failed summoning attempt. However, hearing her sincere plea for help made him change his mind. Leon reconsidered her value to him and then called forth the Greater Flame Elemental Ifrit, which possessed her body.

During her life under Leon, Shizu was forced to work as a powerful combatant, even though she disliked the violence she was forced to commit, but used Ifrit’s power to maintain her human form, refusing to become a full Majin. As the story progressed, Shizu was saved by the Hero, who gave her the Anti-Magic Mask. The Hero Chronoa trained her to control her powers and later became a teacher at Freedom Academy in Ingrassia.

As she reached her 70s/80s, Ifrit’s energy began to fade, and her physical body started to lose stability. Meanwhile, a man named Satoru Mikami died after being stabbed in the streets of Japan. She traveled to the Jura Forest just before Rimuru’s arrival and met him afterward.

3 The Rimuru Era (Current Timeline)

This is the time when Satoru Mikami was reincarnated into a different world as a Slime. This is the time when Rimuru met Veldora and freed him. The current timeline follows the ongoing events of the anime (Season 4). Following Rimuru’s arrival in this world and freeing Veldora, he met with Shizu during her final years. As Rimuru defeats Ifrit, Shizu’s consciousness returned for a short time.

As a final request, Shizu asks Rimuru to absorb her. Devouring her allowed Rimuru to gain a human form, a younger version of Shizu. Rimuru then goes on to defeat the Orc Lord, Geld, and establishes the Jura Forest Alliance. Furthermore, after meeting Milim Nava and awakening as a True Demon Lord during the Falmuth Invasion in Tempest County, this is where we are in the story currently, as shown in the anime series.

It’s worth noting that past timelines are filled with other lore and narrative sets that later shape the events of the timeline. While we did not cover every detail, a more detailed version of the past is available to read on the official Fandom Wiki of the series (via the website). That being said, what are your thoughts on the TenSura timeline and events? Let us know in the comments below.

All Episodes of That Time I Got Reincarnated as a Slime are available to watch on Crunchyroll.