Fulgrim

Hey guys, just wanted to find something out, with skarbrands carnage, if he doesnt fight in the first battle round his stats go to the lower bracket for damage, does that last the rest of the game or just a turn? and can you multiply his carnage rolls by having a blood secrator near him +1attack, and then reapers of vengance comand ability to pile in and do the double attack again= 4 carnage rolls? Cant find any FAQ