Guild Wars 2

I got Transfusion trait and Superior Sigil of Battle.
If I get Reaper’s Might , will its might stack with the sigil ? I will get 4 stacks of might , won’t I ?

What is the cool down of Reaper’s Might effect ? if it has non , I will be able to reach 25 stacks , right ?

Yes the sigil and the (I assume you meant Reaper’s Might trait) will stack, they are both on different cooldowns. Reapers might has no cooldown and with Blood is Power and some might duration runes, we can reach 25 stacks of might easily. I think personally that superior sigil of strength is inferior to blood since the mights offered can be gotten by other means but still need more info.