REDU format ruling
Lost Guardian

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)The original DEF of this card equals the number of your banished Rock-Type monsters × 700.
Rulings
- Whenever the number of your monsters removed from play changes, re-calculate the DEF of "Lost Guardian". (Just like "Shadow Ghoul", etc.)
- NOTE: When a monster is removed from play, it goes to a "removed zone" (for lack of a better term) of the original owner. If the opponent controlled it, it will return to the opponent’s side of the field when it returns to player, however it is considered to be in the original owner’s "removed zone" while out of play. This is important for effects such as "Lost Guardian".
- Monsters removed from play and kept face-down, like with "Different Dimension Capsule" or "Lightforce Sword", do NOT count towards the DEF of "Lost Guardian".
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.