Re:Zero EX1 is about Ferris and Crusch's past. It's a novel which has been officially translated: https://www.amazon.com/Re-Starting-Another-World-light/dp/0316412902/
The part where Crusch finds Ferris is not in the volume, but instead in a separate story. Part of that story has been translated (the part where she finds him) and I'll link it to you once I find it. I don't have a link to it right now.
Here is a part of "The Successor of Blue" short story. Ferris gets the title "Blue" in this story. Only a part of it has been translated:
There are also more short stories about Ferris, but they haven't been translated. Not even parts of them.
She's From this book! And the Anime re:Zero Ex, Vol. 1 Re:ZERO Ex light novel! This volume was written after the anime and its very, very good in my opinion, Its basically standalone, And its pretty tact with Ferris as a character, ~~And its the one where she's revealed to be trans~~
You can find it from places like Amazon https://www.amazon.com/Re-Starting-Another-World-light/dp/0316412902/
You can buy the EX1 novel from places like Amazon. https://www.amazon.com/Re-Starting-Another-World-light/dp/0316412902/
No other Ferris and Crusch side/short stories have been fully translated yet.
It's really really really good. Definitely read it!
First of all, great episode.
Now that we are so close to the end and Ferris the best cat had such a nice scene, let me advertise a little bit.
This right here: https://toptalkedbooks.com/amzn/0316412902
is a special Light Novel volume about Felix/Ferris and Crusch. It's about their past. It's awesome. Read it.
Also, Theleux, can you let me back to the Discord server? I feel lonely. I have learned my lesson.
If you are reading the LN and you don't like Felix/Ferris, you definitely must read this: https://toptalkedbooks.com/amzn/0316412902
He is great.