It's not the idea that he isn't known to other people
The fact is, there's no background on him from our perspective, meaning anything can come up as back story out of nowhere, and we have no clue how it connects or where it comes from

Also, the sword skills, you don't exactly just make your own, it isn't like New Alfheim Online, where they have Original Sword Skills available
There are set Sword skills, so randomly making them without consulting us is just off
Plus Sabres are probably classified as One-handed Curved Swords
So they will have to comply to those sword skills