I'll put it simply - You said you released the Kraken - So going off that, one does not simply release the Kraken and not expect some massive level of devastation to be left in its wake. You opened the door, as the Gm I just took it and ran with it. (Or from it, which ever way you wish to look at it.)

On a personal note, I know your "Kraken" release irl, and it has sent me running and gagging from half a room away. So.... :p I'm just going off personal experience my dear Sigil. Granted this isn't as horrific a response as say Yondar Sex Rocks concert in Subtly Inc, or that frog wanting to "make ribbit" with your svirfneblin, or even Obygns entry to "the house" but hey I work with what I've got.

As far as Keystones Arseblast goes, go talk to the monks, trust me.