Normal
Mjolnir can only fit a 15mm fan in the position adjacent to where your 120mm radiator would go. So you should get another nf-a12x15 instead of the nf-a12x25. I personally have no experience with the Kraken 120, but I believe someone on this thread reported problems installing it in Mjolnir due to the aio tubes being too short. It was several months and several pages back on this thread if I'm remembering correctly. Check into that before you buy it just to be safe.