| Offset | Mask | Description |
| $00 | $F0 | VRAM Map |
| $00 | $0FC0 | Monsters Loaded to BG1 (unused) |
| $01 | $3F | Monsters Present |
| $02 | $FF | Monster 1 Index |
| $03 | $FF | Monster 2 Index |
| $04 | $FF | Monster 3 Index |
| $05 | $FF | Monster 4 Index |
| $06 | $FF | Monster 5 Index |
| $07 | $FF | Monster 6 Index |
| $08 | $FF | Monster 1 x/y Position (low/high nybble) |
| $09 | $FF | Monster 2 x/y Position (low/high nybble) |
| $0A | $FF | Monster 3 x/y Position (low/high nybble) |
| $0B | $FF | Monster 4 x/y Position (low/high nybble) |
| $0C | $FF | Monster 5 x/y Position (low/high nybble) |
| $0D | $FF | Monster 6 x/y Position (low/high nybble) |
| $0E | $3F | MSB of Monster Indexes |