Proper storage and care for your knives is the whole story of these knife rolls.
It's just one of the reasons these knife rolls are lined. I will never make a knife roll where the leather comes in contact with your knives, nice looking as they are. That said, I make all of the goods here and all of the leather comes from U.S. tanneries. Your knives deserve the caution. Please read and see the comments on this link from leather crafters.

"leathers tanned in non-commercial settings and tannages from less developed countries that don't follow modern tanning processes. The reason for this is that "you just don't know what these guys are doing, there's some, uh, pretty funky stuff out there. I mean chemically its all backwards, but it works somehow."
"Any corrosion risk comes from storing the gun/knife/etc. in leather-- the leather absorbs moisture from the surrounding air and creates a damp environment. Damp environments and metals don't mix."
https://www.reddit.com/r/Leathercraft/comments/4y005l/solved_can_chrome_tanned_leathers_be_used_for/

Veg tanned leather sheaths are okay if you use a knife extensively, but for long term storage choose a natural(unbleached) cardboard sheath or if you live in a very humid area, a heavy plastic bag with no holes and a desiccant (silica packet) and a small amount of oil on the blade only to prevent water spots and oxidation from forming.

More knife care tips:
https://knife-depot.com/pages/knife-care-and-maintenance

This is mostly about folding knives but the care tips are not any less relevant:
https://www.sogknives.com/knife-tool-care.html

How I got here:
It all started when my son was 4, or maybe 3 and he wanted to cook eggs. He did and then he graduated Culinary School. I know, big gap there, but he designed a knife roll he wanted me to make, I did and I was off and running. It was more than a little different than the current one.
The current knife roll is the result of a couple years of learning about the best way to store knives so they have the least tendency to rust or corrode. About how Leather and Ballistic Nylon behave, age and how one complements the other so they stay in shape. How to sew on an industrial machine, about pattern making and then sewing prototypes that were tested by chefs. Many failed and this one succeeded, really well. It keeps knives secure, dry and convenient.
I have been designing and creating my whole life, making anything has always been my calling, sewing is just one of my outlets but probably my favorite.

I feel these cases chose me and I love making cases and bags that are practical, appealing and will last a lifetime.