Settlers -> Engineers
       defense_strength:   1  -- >    2  +100%
              move_rate:   3  -- >    6  +100%
                  flags: +Transform
 
 Warriors -> Pikemen
             build_cost:  10  -- >   20  +100%
       defense_strength:   1  -- >    2  +100%
                  flags: +Pikemen
 
 Phalanx -> Pikemen
                  flags: +Pikemen
 
 Archers -> Musketeers
       defense_strength:   2  -- >    3  +50%
                     hp:  10  -- >   20  +100%
 
 Legion -> Musketeers
             build_cost:  40  -- >   30  -25%
        attack_strength:   4  -- >    3  -25%
       defense_strength:   2  -- >    3  +50%
                     hp:  10  -- >   20  +100%
 
 Pikemen -> Musketeers
             build_cost:  20  -- >   30  +50%
        attack_strength:   1  -- >    3  +200%
       defense_strength:   2  -- >    3  +50%
                     hp:  10  -- >   20  +100%
                  flags: -Pikemen
 
 Musketeers -> Riflemen
             build_cost:  30  -- >   40  +33%
        attack_strength:   3  -- >    5  +66%
       defense_strength:   3  -- >    4  +33%
 
 Horsemen -> Knights
             build_cost:  20  -- >   40  +100%
        attack_strength:   2  -- >    4  +100%
       defense_strength:   1  -- >    2  +100%
 
 Chariot -> Knights
             build_cost:  30  -- >   40  +33%
        attack_strength:   3  -- >    4  +33%
       defense_strength:   1  -- >    2  +100%
 
 Knights -> Dragoons
             build_cost:  40  -- >   50  +25%
        attack_strength:   4  -- >    5  +25%
                     hp:  10  -- >   20  +100%
 
 Dragoons -> Cavalry
             build_cost:  50  -- >   60  +20%
        attack_strength:   5  -- >    8  +60%
       defense_strength:   2  -- >    3  +50%
                  flags: -Horse
 
 Cavalry -> Armor
             build_cost:  60  -- >   80  +33%
        attack_strength:   8  -- >   10  +25%
       defense_strength:   3  -- >    5  +66%
              move_rate:   6  -- >    9  +50%
                     hp:  20  -- >   30  +50%
 
 Catapult -> Cannon
        attack_strength:   6  -- >    8  +33%
                     hp:  10  -- >   20  +100%
 
 Cannon -> Artillery
             build_cost:  40  -- >   50  +25%
        attack_strength:   8  -- >   10  +25%
              firepower:   1  -- >    2  +100%
 
 Artillery -> Howitzer
             build_cost:  50  -- >   70  +40%
        attack_strength:  10  -- >   12  +20%
       defense_strength:   1  -- >    2  +100%
              move_rate:   3  -- >    6  +100%
                     hp:  20  -- >   30  +50%
                  flags: +IgWall
 
 Fighter -> Stealth Fighter
             build_cost:  60  -- >   80  +33%
        attack_strength:   4  -- >    8  +100%
       defense_strength:   3  -- >    4  +33%
              move_rate:  30  -- >   42  +40%
 
 Bomber -> Stealth Bomber
             build_cost: 120  -- >  160  +33%
        attack_strength:  12  -- >   14  +16%
       defense_strength:   1  -- >    5  +400%
              move_rate:  24  -- >   36  +50%
 
 Trireme -> Caravel
        attack_strength:   1  -- >    2  +100%
     transport_capacity:   2  -- >    3  +50%
                  flags: -Trireme
 
 Caravel -> Galleon
        attack_strength:   2  -- >    0  -9999%
       defense_strength:   1  -- >    2  +100%
              move_rate:   9  -- >   12  +33%
     transport_capacity:   3  -- >    4  +33%
                     hp:  10  -- >   20  +100%
 
 Galleon -> Transport
             build_cost:  40  -- >   50  +25%
       defense_strength:   2  -- >    3  +50%
              move_rate:  12  -- >   15  +25%
           vision_range:   1  -- >    2  +100%
     transport_capacity:   4  -- >    8  +100%
                     hp:  20  -- >   30  +50%
 
 Frigate -> Ironclad
             build_cost:  50  -- >   60  +20%
       defense_strength:   2  -- >    4  +100%
     transport_capacity:   2  -- >    0  -9999%
                     hp:  20  -- >   30  +50%
 
 Ironclad -> Destroyer
              move_rate:  12  -- >   18  +50%
           vision_range:   1  -- >    2  +100%
 
 Cruiser -> AEGIS Cruiser
             build_cost:  80  -- >  100  +25%
        attack_strength:   6  -- >    8  +33%
       defense_strength:   6  -- >    8  +33%
                  flags: +AEGIS
 
 Diplomat -> Spy
              move_rate:   6  -- >    9  +50%
           vision_range:   1  -- >    2  +100%
                  flags: +Spy
 
 Caravan -> Freight
              move_rate:   3  -- >    6  +100%
 
 Explorer -> Partisan
             build_cost:  30  -- >   50  +66%
        attack_strength:   0  -- >    4  +9999%
       defense_strength:   1  -- >    4  +300%
                     hp:  10  -- >   20  +100%
                  flags: -NonMil
 
 Barbarian Leader -> Settlers
       defense_strength:   0  -- >    1  +9999%
              move_rate:   6  -- >    3  -50%
                     hp:  10  -- >   20  +100%
                  flags: -IgZOC
                  flags: +Settlers
                  flags: +Airbase
                  flags: +Cities
                  flags: +AddToCity