Thank you for asking :)
The Kasys or Kasys Multiverse is a worldbuilding project centered around an alternate version of Earth and several other dimensions.
The first thing related to the Kasys ever was made in 2017/2018 by me and my (at the time) friend Benedikt being simple bastardised childhood drawings of characters from various games and series (I swear this is important later). After a falling out with Benedikt, I began writing stories using us and other people as the characters, also including characters from many different media.
In 2020, a Minecraft superflat world was created, which would eventually develop into the country of Popistan in its current form. Me and my best friend Luna kept making new servers and making countries on them that were all interconnected in lore. A world map server, SPWM, was created, which became very important for the establishment of Kasys Earth. Many countries from SPWM and these other servers were ported over into what would eventually become the Kasys Earth and other dimensions. In 2023, a member who now no longer works with us joined the team, coining the term Kasys and helping with the establishment of Kasys dimension logistics. My two other best friends, Wasd and Heavy, as well as another friend, Dosh, also made countries in the Kasys in 2024, and since then, many changes have happened, mostly in Kasys Earth and Popistan, but also in other dimensions such as the Greater Popistani Archipelago, Hwrynia, and MistakeModded.
The previously drawings and stories from the Benedikt era were repurposed into Kasys mythology, particularly the Siqqelist and Hinkelist religions of Popistan. This is why I consider them to be the true start of the Kasys project.
I also have six derivative projects not part of the Kasys canon, as well as SPWM and one derivative project of it.
There are currently 503 countries and territories in the Kasys (not counting uninhabited/unclaimed areas). There are 27 dimensions/planets.
I would describe the main topic of the Kasys, particularly Popistan, to be about equality and cultural preservation, which can be seen in the extensive list of Popistan's national languages and the continued decolonisation efforts on Earth.
If you want to read about the Kasys, I recommend this (that is the page on Popistan because I haven't written anything else on the wiki yet).