Roghrax has printed values 2 ATK and 5 HP, plus Brutal and also Bloodthirst, and the text "during a combat round in which 1 or more units have been destroyed at this planet, double this units ATK".
If, for example, Roghrax has received 1 damage, then Brutal makes his ATK to be 2 + 1 = 3. Then, if Bloodthirst were to apply, would Roghrax's ATK become:
a) Double his printed ATK of 2, x2 = 4, plus 1 for Brutal = 5?
Double his current ATK of 3, x 2 = 6?