[konart]

Originally Posted by rinichan

sorry its no spin off.
its part of the original cg timeline. so its canon.

In media, a spin-off, sometimes called a sidequel, is a radio program, television program, video game, or any narrative work, derived from one or more already existing works, that focuses, in particular, in more detail on one aspect of that original work (e.g. a particular topic, character, or event).

- wiki

It's part of the original cg timeline, but focuses on different characters. That is why it is called spin off. Just like Gundam SEED Astray for example