First Snow

I tried taking Utopia with Towers. Doesn't the Tower mostly have damage that's effective against Naga?
And in Utopia, Dragons immediately attack Naga first, even Royal Naga, even if there are 11 of them. Apparently, they consider Naga to be easy prey. What needs to be done so that the dragons don't attack the Naga?

Well, in the first Utopia level, I didn't even take Gremlins or Mages; I took 50+ Centaurs and 7 Djinns, plus a few single units. The dragons ate them because their stats were already decent. If you don't take single units but stacks that the dragons won't be "afraid to fight back" against, then they will devour them. In the next Utopia levels, I defeated them with Pandorian units.