Which starting-level magic is the best in Utopia?

Yes, I was lucky. As for troops, I had 40+ pikemen, about 14 griffin riders, and around 400 skeletons ;) and 12 vipers. There was just a lot of air units, and I got lucky. Double strike triggered for the griffin riders and skeletons. And then again for someone else. In short, it happened three times in one battle. And that's doubling the strike. I'm just curious - if you calculate, what's the best thing to use here? In my opinion, this magic. The main attack in the 1st round is directed at me, so it's already too late to use defense - is mass blood (+6 attack) better? When the enemy already has a significant advantage in attack/defense? ;)