User blog comment:Valeth/Alter Ego of τ/@comment-25848535-20190418211340/@comment-25848535-20190419203821

I think if you simply put it as "Boost Extra Card performance by X%", then the card would simply gain more Damage, Stars, or NP, which depend on the opening card. If it is a pure type brave chain (QQQ/AAA/BBB), then the Extra card would basically considered as a 4th Q/A/B card, the effect can be very Stronk.

I am sure you can come up with some interesting ideas! Looking forward to see them! =D