Very useful if you use a deck based on amazoness monsters. Boosting the ATK of all amazoness monsters by 1000 allows them to beat even high level monsters. Note that they do not gain ATK when they are attacked by monsters your opponent controls in the opponent turn.
The text should state it only applies to the controller, it is indeed incorrect. (The TCG text has the same issue.) Continuous Spells can apply to both players (Machine Assembly Line does for example). Heck, Field Spells don't always do so either. (While most older ones do, a lot of newer ones don't, such as Sorcerous Spell Wall.)
The way Fighting Spirit is worded in the TCG, it "should" work for both players. But that isn't what was intended (it even had/has TCG rulings saying it only worked for the controller's monsters), or how it is worded in the OCG.
In general, if a continuous effect doesn't mention a specific player, it works on both. They just screwed up in this case.
" Anonymous Reply
Read the card effect and the OP's question more careful you stupid anon!
fighting spirit only raises the amazoness's attack IF the monster it's fighting has a higher attack. Unhappy girl doesn't have higher attack!
Personally I think the OP is just high and/or making 🔥 up.
Weird, someone I dueled in the kaiba cup had this but it’s still unavailable?