Fog of war keeps the tension high and makes this game full of surprises:
Every unit has a LOS (line of sight) range of 2 tiles and natural obstacles could hide many things.

This example (in Multiverse War, every battle, every game, is a story worth telling!):
Red player is wondering what kind of army composition does blue have. He knows he has 3 action points with his Shield Maiden so he first advances to the grassland adjacent to the unit hidden in the forest, spending only one action points. That allows Shield Maiden to retreat even to the hills where she came from (in case the red player estimates the units he reveals are too strong for him). He reveals one Heavy Swordsman and the Archer on the hill behind. He then decides to take a small risk and moves the Shield Maiden into the forest adjacent to the Swordsman. Forest gives him decent protection against ranged attacks and he had no other way of revealing the third enemy unit. Also it is a bit of a gamble but, this way he tries to push the blue player into action. Blue now has a chance of killing that Shield Maiden but the red player carefully approaches his Berzerker to the nearby forest.
Why to that forest hex? Because that way the blue player cannot see his unit. Shield Maiden is the target of opportunity here since she is the Viking player special unit. The red player estimated that Shield Maiden will do at least 1 damage to enemy units. Even if she dies, the Berzerker will be in range to finish off any enemy unit which will eliminate the Shield Maiden and take its position.

Ideally for the red player, it will be the enemy Horseman. Heavy Swordsman has heavy armor, reducing chance to hit of all hand to hand attackers.
Why is that a great trade? Berzerker is Viking player's tier 2 unique unit so, his strongest unit. He needs to grow all Berzerkers in power and he can achieve that only through winning battles.

Bluffing and fake units:
Something I haven’t foreseen at start (so I was sold that trick) is players bluffing: moving hidden units as if they have 2 action points, until the opponent comes closer only to reveal those are horses (they can advance 4 tiles in one turn)! That can be very dangerous if they catch you off guard. I lost a builder like that early on and it slowed down my development considerably.

Also, realizing players loved bluffing, I added decoys and bluffing combat card which each player possesses.
Decoys can be placed for no gold cost at the same time as you recruit your army. That way your opponents don't know what you built for sure, even if they carefully follow your treasury cool. Decoys can fake a Builder, an infantry unit, cavalry unit...whatever you wish!
Bluff combat card is given to each player at start of the game. Unlike other combat cards, this one can be used once per turn and is always returned to the player's hand at the end of the turn.
All other combat cards are discarded once they are used. You do have to buy then from the trade deck so make sure to use them wisely.