Favorite hero companions for the campaign

Hi guys,

I was wandering what are your favorite units to use as companions in the campaign.

I tend to find Spider Priestesses some of the most effective without being OP.

I think the most powerfull are the Minotaur Kings... but they just break the classic campaign because they are just OP.

What units do you use?.

Dragon Knights, Naga, Ancient Wisps.

Generally I prefer units that aren't too squishy, because it's hugely frustrating to lose a long-reared companion to a moment's inattention.

The absolute best has to be the Ancient Treant imo.

A lv 50 AT can cast a very high level Entangle on an enemy hero/army and slow them to a crawl, it has monstrously high combat stats, it can summon Oakmen for use as builders or mine fillers, and can quite reliably act as the tip of the spear for a whole army, tank titans, assassinate heroes, and bodyguard your squishy mage hero against fast assassins going after you for a cheap kill.

In combination with my Knight Grand Oracle who just focused on spamming Divination and Arcane spells (like summoning f***tons of mages for damage support) it was extremely hard to stop even on Hard difficulty during the campaigns.