Talk:Invincible Defense/@comment-2001:D08:1100:5CD:B4A7:2593:2F9E:6B7A-20171127150223/@comment-28089742-20171127150728

Normally yes, farm 5 of the same card to level up a skills CD. If you're lucky enough, the skills CD will jump three times (like CD slvl 7 to CD slvl 10).

Well if you have tones of Baby Harpy, you can use more of them to speed up a skills but will not recomended.

As for Harpy, this option is last resort, as in depending on the stage's difficulties or if there's no skill feeders at all. Qi Tian Di is one of the example I'd rather use Harpy instead to refight that stage.