As with most Auto Chess games, it's possible to both combine and upgrade units in Dota Underlords in order to make them more powerful (and free up some much-needed board space).
Once upgraded, your units will be able to do a great deal more damage, thanks to enhanced abilities.
As you make your way towards the latter stages of a game, boosting existing units tends to be much more important than simply bulking out your board with multiple characters and synergies.
How to combine and upgrade units
To combine a unit in Dota Underlords to a two or three star rank, you need to follow these steps:
- Start with a single unit on the board
- Purchase two more of those same units to upgrade the starting unit to 2 Stars.
- To reach 3 Stars, purchase nine copies of any given unit
That's as far as you can take the upgrade path. Note that any items consumed during the upgrade process will be popped back into your pile, and you'll need to reassign the item.
The process is completely automatic. If you have two active units on the board and purchase a third, then they'll combine into a single 2 Star unit.
Keep in mind that this may free up some space on the board. You want to utilise all of your unit potential in the upcoming round, so think about whether or not you need to fill out that space with something else.
How to combine and upgrade Druids
Combining Druids in Dota Underlords can be particularly confusing process if you're new to the game, but once you get the hang of its unique system, you'll find it's plain sailing.
Upgrading Druids Permanently
Individual Druid units upgrade in the same way as any other hero.
- If you want a permanent two star version of a Druid hero, you need to purchase three one star versions.
- If you want a permanent three star version of Druid hero, you need to work towards owning three two star units.
How does the Druid Alliance affect things?
Here's where it gets a bit complicated.
Druids can increase each others' star levels temporarily thanks to their special Alliance buff. Let's start by breaking down how the Alliance works:
- 1) If you have 2 different Druid heroes on the board, the lowest star ally Druid is upgraded a level.
- 2) If you have 4 different Druid heroes on the board, the two lowest star ally Druids are upgraded a level each.
Next, here are all the heroes which count as Druids:
- Lone Druid
- Nature's Prophet
- Treant Protector
First rank of the Druid Alliance Bonus
So, if you place one, one star Enchantress and one, one star Treant Protector (note: two different Druid units, not two of the same units) on the board, this will activate the first rank of the Druid bonus listed above.
This means that at the beginning of each round, either your Enchantress or your Treant Protector will be temporarily upgraded to a two star version for the duration of that round.
Let's say you have one, two star Enchantress on the board, and one, one star Treant Protector. Again, because you've got two completely different Druids on the board, you'll activate the first rank of the Druid bonus. However, because your Enchantress is already a two star unit, the Treant Protector will always temporarily upgrade to a two star version at the beginning of every round.
Second rank of the Druid Alliance Bonus
To activate the second - and highest - rank of the Druid Alliance bonus, you'll need all four Druid heroes on the board at the same time.
Let's say you have one, two star Enchantress and one, two star Lone Druid, followed by one star versions of Nature's Prophet and Treant Protector on the board.
The second rank Druid Alliance bonus means that the two lowest star Druid heroes on the board will be upgraded a level. So, the Nature's Prophet and Treant Protector will temporarily upgrade at the beginning of each round.
Finally, let's say all four of these Druid heroes on the board are two star units. This would mean two randomly selected Druids will temporarily upgrade to three star units at the beginning of each round.
That's everything you need to know about upgrading and combining units in Dota Underlords.