Monsters Special Summoned that same turn after activation of “Staunch Defender” must also attack the monster selected by “Staunch Defender”.
If your monster selected with “Staunch Defender” is destroyed, your opponent’s remaining monsters cannot attack.
When your opponent chains “Ring of Destruction” to your “Staunch Defender” to destroy the selected monster, the effect of “Staunch Defender” is negated and battle is conducted normally.
While “Staunch Defender” is active, your opponent must still pay costs to attack with “Dark Elf”, etc., if he/she attacks with that monster.
You cannot select “Guardian Kay’est” or “The Legendary Fisherman” for “Staunch Defender” if they cannot be attacked.
You can activate “Staunch Defender” when a monster affected by “Diffusion Wave Motion” declares an attack. The monster affected by “Diffusion Wave Motion” will then attack your selected monster once (and only once).
When you select “Spirit Reaper” or “The Reaper on the Nightmare” as the target of “Staunch Defender”, resolve the chain, and after the effect of “Staunch Defender” resolves, the selected monster is destroyed. A replay will occur, but the opponent can no longer attack because the selected monster is gone.
If two “Staunch Defenders” are activated during the same turn, the last one to resolve will be the one that applies.
If “Absolute End” and “Staunch Defender” are both activated during the same turn, the last one to resolve will be the one that applies.
Netrep Rulings:
Monsters summoned after “Staunch Defender” resolves must attack the designated monster.
If the monster designated by “Staunch Defender” is destroyed or leaves the field, the opponent’s monsters may no longer attack.
“Staunch Defender” may only designate a legal attack target.
Monsters that have attacked before “Staunch Defender” was activated may not attack again, unless that monster was able to attack a second time normally.
Netrep Q&As:
Q: If “Thousand-Eyes Restrict” declares an attack and the opponent activates “Staunch Defender”, will all other face-up monsters have to attack?
A: It depends on “Thousand Eyes Restrict” surviving the attack. If the “Thousand Eyes Restrict” survives the attack (due to Battle Damage or its effect), then no other monster will be allowed to attack. If it does not survive and is sent to the Graveyard or otherwise removed from the field, then any other face-up monsters on your side of the field would have to attack the selected monster. Curtis Schultz, 02/01/2004