Upgrades are purchased at your guild house with lanterns, unlocking new characters for hire, strengthening your Master Thief, and even scoring bribes for Victory Points.
Every time you spend either currency on a unit or upgrade, the price of a subsequent purchase goes up. This means that every time you spend Lanterns on an upgrade, you will have to spend the asking price plus one next time around. It's a similar story when it comes to money, but this “tax” is only incurred when buying multiples of the same unit. Be sure to diversify your investments!
Each turn you can also choose to purchase a Bribe for 5 lanterns (7 for the second and 9 the third) or choose charity instead, giving you 4 gold or 2 lanterns.
Upgrade tree[ | ]
| Cost |  |  |  | ||||||||||||||||||||||||||||||||||||||||||||||||||||
 |  (Infiltrate businesses.) 1 free Urchin. |  |  (Attacks enemies; evicts urchins.) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|  (Guards tiles, joins Gangs.) 1 free Thug. |  (Traps a building or reveals a District.) 1 free Saboteur. |  |  (Burgle Art from Estates for 2 lanterns.) |  (Master Thief can attack once per turn for 1 Damage.) | ||||||||||||||||||||||||||||||||||||||||||||||||||
|  (+1 Thug Health.) |  (Burgle jewelry from Estates for 4 gold.) |  |  (Master Thief can attack once per turn for 2 Damage.) |  | ||||||||||||||||||||||||||||||||||||||||||||||||||
|  (+1 Thug Health.) |  (6 damage attack. One-time use.) 1 free Assassin. |  (Evicts all Urchins from a business.) 1 free Officer. |  (Master Thief can attack once per turn for 3 Damage.) |  | ||||||||||||||||||||||||||||||||||||||||||||||||||
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