Party buff bond CE

I'm assuming you're talking about Mozart.

1. His Bond CE only boosts NP damage, not regular damage.

2. His Bond CE only activates if, and ONLY IF, he is on the field. In other words, if he's in your back line, the effect won't be triggered.

3. His Bond CE only activates if he himself is equipping it.

4. Except for health demerits, most CEs will not show obvious signs of the effect (s). For example, CEs boosting attack damage will not have the attack buff sign displayed when attacking (though the increased damage dealt to enemies is pretty obvious).