Haven buildings.

Golems have magic resistance, not immunity or partial immunity, so all buffs work perfectly on them, except for those that only affect living creatures. And, of course, teleportation will also work.
As for mages, in my opinion, in the final battle (if they even appear), they are not a unit worth protecting. As soon as their turn comes, feel free to poison the hero or, if he has high resistance, some other important unit. And then, if no one wants to attack the mages, you can start shelling them and continue poisoning them, and sometimes it can be useful to raise skeletons.

I don't know, I don't know, I just remember a case when I tried to cast bless on a creature with resistance, and it calmly reflected it :( Anyway, I think golems are quite annoying - in my army, they are a rare hindrance, and if they are on the enemy side, it's hard to defeat them without a fight :smile35:
Whether you pity the mages or not, they will still be defeated :D But the poison cast by a hundred mages (if we are talking about the final battle, then this number is more than realistic) will cause so many problems that it will be more expensive to deal with them.