Board Thread:Questions and Answers/@comment-63.166.115.40-20150102231051/@comment-24516590-20150103202337

Active Skils that don't share the same effect do stack. So in your situation, Machines would get 3x attack (2x from saber times 1.5x from Charlotte), all other Units would just get Saber's 2x.

If two multipliers share the same icon, however, they will not stack. The first one you used takes precedence, but in most cases, you won't be able to even activate a second skill. For example, Dante's Active increases God type and Fire Type attacks by 1.75x, but you can not stack it with Surt's active, which increases Fire Type attack by 2x, afterward. You can, however, use Surt's active before using Dante's to make the final result 2x to Fire and 1.75x to Gods (totalling to 3.5x to Fire Gods).