My actions have perhaps engulfed the entire island in war. The Norse have been turning gathering allies to join in their crusade against me, so I've been forced to divert those foes by paying massive subsidies to Powys, Mercia, the Irish, and the Picts to have them join in nominally on my side. Not sure how things are going down south due to my meddling, but Gwent's attack was successfully blunted by a big force of pagan thegns. A settlement culture flipped, forcing the beserks to waste turns recapturing it. My fleet picks off random longboats, while my mounted thegns ambush isolated Viking raiders. No major clash with the mega stacks yet, though I continue to shadow them with my army and horde of soakingmen. Not sure if I have enough hirthmen to survive their counter-stroke.
Oh, and the Danes had a protection pact with the Norse, so now they're involved too......(I'm sure it'll be fine)