- Mei appears in the artwork for and is quoted in the descriptions of , , , and .
- Red and Blue appear in the artwork for and are quoted in the descriptions of , , and . They also appear in the artwork for and , and Red appears in the artwork for .
- Mei and Red & Blue use their designs from the game Xmas Shooting - Scramble!!, rather than their designs from QP Shooting or Christmas Shooting. Mei used to have twintails and a hoodie in QP Shooting and long hair with winter gear in Christmas Shooting while Red & Blue used to be more round and plump.
- Their first appearance was as the boss of the first stage of QP Shooting. They also are the only characters other than to appear in both QP Shooting and Christmas Shooting.
- Red & Blue also appeared in Acceleration of SUGURI X-Edition, fighting alongside .
- Mei is 13 years old in Xmas Shooting - Scramble!!
- Red & Blue are both 2 years old in Xmas Shooting - Scramble!!