Does anyone know what knife elder brother 12 and 12450 are?

There used to be an anchor named 12dora, the anchor MC. Later, many people came to play with the old server. Many people need an invitation code to get in when they get stuck. At that time, the invitation code was 450 BBS coins, which was later misrepresented as "You can make friends with 12dora by paying 450 soft sister coins".