The hills are alive with the sound of bloodshed, usually. It just happens that hills are usually the best place to take a fight in Age of Empires 2, so long as you have the height advantage. I’m going to flip the script on this article and put the conclusion at the start, things get pretty hot and heavy in here thanks to the way that Age of Empires handles rounding and all of the other considerations regarding hill bonuses. However, the main takeaway is that hills are very good (if you’re at the top).  Try to avoid fighting uphill, try to take fights downhill and remember that hills affect units and buildings alike. For information about cliffs there’s a section specifically for them further down the page.

That’s right, if you’re fighting uphill then it’s going to be an uphill battle. Any unit attacking something that is higher than it will suffer a 25% attack reduction. While anything attacking downhill will benefit from a 25% attack increase. This is huge and can absolutely make the difference between victory or defeat when taking an engagement. It also doesn’t matter how big the hill advantage is, whether the unit you’re attacking is 1 tile below you or 6 tiles above the 25% bonus is the same.

No Funny Business

Archers with even upgrades. The archer on the hill survives with 15HP (50%!). The Blue archer does 5 damage per arrow while the Red archer does 3.

Armor Before Or After?

When you introduce armor, is the bonus damage calculated before or after armor is considered? Surprisingly it’s calculated after armor reduction. For example: an Arbalest with 8 attack should be expected to do 10 damage with the hill bonus. Against a unit with 4 armour we would assume that 6 damage would be dealt if the armour was taken after the bonus damage. However, only 5 damage is dealt, meaning that the 4 armour is applied first and then bonus damage is calculated. 8 damage minus 4 armour is 4 attack. Given the 25% bonus it increases to 5 damage. 

Does Bonus Damage Count?

Yes, it absolutely counts and can rack up some insane bonus multipliers. A great example of this would be a halberdier vs a war elephant. Halbs have +60 bonus attack versus elephants and 6 base damage. With the 25% bonus they do 75 damage, non-negotiable, as bonus damage goes straight through armour. They then inflict an additional 1 damage from their base attack minus the elephant armor. This means you will damage the elephant for 82 on your first strike with a halberdier! That’s the highest single strike possible from a non-siege unit in the game. (Higher still if you have attack upgrades).

A Fractional Advantage

Things start to get pretty funky with the crossbowman example shown here. If we take the 5 damage of the blue crossbow and add the 25% bonus we get 6.25. However, the first arrow that hits the red crossbow will do 7 damage! After that the next three arrows will each do 6 damage and then then the cycle will repeat. 1x7 damage, 3x6 damage and so on.  If we add the damage from the 4 arrows together and divide by 4 we see that the average damage per arrow is 6.25.

This means that the .25 damage that would be inflicted by 4 arrows is being added all at once instead of split over each shot. It also means that we get the extra damage up front, another win for the hill huggers!

Also note from the table here that while the bonus damage from the Blue Crossbow comes up-front, the damage reduction from the Red Crossbowman comes at the end. This helps to spread out the damage discrepancy over the course of the battle.

Of course, we’re looking at this in the isolation of a 1v1 to study the effects. In a group battle the damage is also spread evenly. So for example: if you have 5 crossbowmen they won’t all inflict 7 damage with the first arrow to the same target. Instead the damage will still follow the same pattern as we’ve seen.

Blue HP

35

31 (-4)

27 (-4)

23 (-4)

20 (-3)

16 (-4)

12 (-4)

Red HP

35

28 (-7)

22 (-6)

16 (-6)

10 (-6)

3 (-7)

0 (-6)

An important thing to note here is just how big of a difference the hills make. In all of the examples above the blue unit with the hill advantage took significantly less damage. Without micromanaging your units you have a big advantage and with a bit of extra effort you can massively increase your damage output. This is particularly strong in the early game when you have fewer units on the map. 

The Bonus Is Too Damn High

And it’s about to get higher. Introducing: Micromanagement, coming to a game near you. Remember our first example of two archers; the Blue archer survived with 50% of its HP remaining. This makes sense since it had an attack bonus of 25% and the enemy had a reduction of 25% for a net of 50%. But can we push past that? Of course we can. 

Now imagine a scenario where you have two archers and your opponent has two. Watch the video to see what happens. Both archers survive, but while one has 15 HP the other survives with 24. This gives our two archers a combined health pool of 39/60 which is 65% of their starting health, a massive improvement from our first example. 

We can push this even further with larger groups. With a group of 6 archers you can one-shot enemy archers and if you task your archers to shoot one at a time you can win the battle with 75% of your health pool remaining. We’re starting to get into the realm of Lanchester’s Laws and Overkilling now, you can read all about those topics in depth with the links provided. However, the main take home is that hills can be used to devastating effect in the hands of a competent player. 

Cliffs

How do they work? Similar to hills cliffs do give an attack bonus to the unit “on top”, but they do not give an attack reduction to the unit below. This gives a one-way bonus of 25% to whoever controls the top portion of the cliff, which isn’t as good as a hill but definitely a lot better than nothing.

Cliffs & Hills

What happens if you combine them? A cliff on a hill will be ignored and the hill bonus will be taken into account instead. The Blue archer deals 5 damage while receiving just 3. The cliff bonus doesn’t stack at all with the hill bonus.

This combination is quite possibly the most interesting. When there’s a hill at the bottom of the cliff the Red archer is technically on a higher elevation than the Blue one. But the Blue archer still recieves its 25% attack bonus from the cliff with no reduction from the Red archer being on the hill. Meanwhile the Red archer gets their 25% attack bonus for being on a hill. The result is that both archers do 5 damage to eachother. If you combine cliffs and hills then everyone’s a winner!

Buildings

Like units buildings can also benefit from the hill bonus. Units attacking a building which is above them deal 25% less damage and the same is true in reverse. This is especially important when building castles, as Siege units have huge attack bonuses against them. A trebuchet for instance has 250 bonus damage against all buildings. That’s 302.5 bonus damage when attacking your castle which you decided to build in a pit for some reason. Not to mention the 200 base damage which becomes 236.25 when the hill is taken into account.

A castle in a pit can survive 8 hits from a treb before going down, while a castle on a hill can survive 14. I know what I’d prefer!

Bonus damage also applies to buildings that fire arrows, but the bonus isn’t very impressive at all. A castle which fires 5 arrows, each doing 11 damage, will only inflict 58 total damage when firing downhill. This is because the bonus damage is only applied to the first arrow and not all 5. An increase of just 3 overall damage is tiny and barely improves your castle at all.

This also explains why Watch Towers shooting at eachother don’t seem to be affected by hill bonuses. A Watch Tower has a pierce armor of 7 but a base attack of just 5. This means that two Towers attacking eachother will always do 1 damage regardless of the hill positionings. As we also learned: the hill bonus is only applied to the first arrow. So any extra arrows from garissoned units provide full damage. You can read more about garisson arrows here.

Thanks for reading! If you made it to the end there’s no conclusion because I put it at the start (oops). So here’s a fun fact for making it this far: the highest possible damage in one hit is the Petard when exploding downhill against a Stone Wall. It will do a whopping 1752 damage in a single hit!