Talk:Lord of Shadow - Erebus/@comment-28089742-20170213140427

I already used 5 Baby Harpies then used 5 Harpy again to max out these kind of hard-to-farm active skills. Why? Cause their source (minions of related active skills) to farm is really limited, quite hard and also not guarantee drop, in the end, you use up MORE diamonds just to farm their active skills than you've expected.

On the other hand, at least Harpy you'll get it FREE every Friday, just that you need to have patience to max out a card.