When using in a deck that Inferno already in play, it should just give that Inferno Atk+5 Df-2 without replacing anyone.
But what actually happened is it give Inferno atk+5 df-2 and also let me choose a character to replace to another Inferno. And the new Inferno didn't have Atk = 15 like the text said, it's just a lv.1 Inferno with Atk = 8.
Here is the screenshot, the left most character become another Inferno with Atk = 8.
http://imgur.com/a/nqIYJ
