In the forge you create equipment for your Hero with the materials you collected. You can only have one of this building.
Upgrading the forge is a necessary step before upgrading the Wall, thus, the Palace. Upgrading requires a big quantity of iron, most than any other building. Upgrading the forge does not grant significant bonuses (only a small bonus to equipment crafting speed), but it is a test to check the player capacity to gather and stock increasing quantities of iron.
Requirements: You can only upgrade the Forge if you have at least one Mine already upgraded to the same level as you are trying to upgrade to. Example; If you want to upgrade the Forge to level 14 then you must have at least one Mine that is upgraded to level 14 or more.
Cost
Level
Food
Lumber
Iron
Stone
Gold
1
150
200
400
150
15
2
255
340
680
255
25
3
435
580
1200
435
45
4
740
985
2000
740
80
5
1300
1700
3350
1300
130
6
2550
3350
6700
2550
210
7
5050
6700
13.5k
5050
335
8
10.5k
13.5k
27k
10.5k
490
9
20.5k
27k
53.5k
20.5k
700
10
30.5k
40.5k
80.5k
30.5k
1150
11
45.5k
60.5k
125k
45.5k
1250
12
68.0k
90.5k
185k
68.0k
1600
13
105k
140k
275k
105k
1750
14
155k
205k
410k
155k
1900
15
230k
305k
610k
230k
2050
16
345k
460k
915k
345k
2400
17
515k
690k
1.4M
515k
3250
18
775k
1.0M
2.1M
775k
4700
19
1.2M
1.5M
3.1M
1.2M
8900
20
1.7M
2.3M
4.6M
1.7M
14.5k
21
2.6M
3.5M
6.9M
2.6M
54k
22
3,9M
5,2M
10,5M
3,9M
80k
23
5.9M
8.0M
16.0M
5.9M
120k
24
25
12,2M
16,3M
32,2M
12,2M
390k
26
Gain
Level
Hero's XP
Influence
Increase
Crafting Speed
1
+5
+5
+5%
5%
2
+15
+10
+5%
10%
3
+25
+20
+5%
15%
4
+100
+30
+5%
20%
5
+200
+45
+5%
25%
6
+250
+65
+5%
30%
7
+250
+100
+5%
35%
8
+250
+150
+5%
40%
9
+250
+230
+5%
45%
10
+250
+345
+5%
50%
11
+250
+515
+5%
55%
12
+250
+775
+5%
60%
13
+250
+1150
+5%
65%
14
+500
+1700
+5%
70%
15
+1000
+2600
+5%
75%
16
+1250
+3900
+5%
80%
17
+1250
+5900
+5%
85%
18
+2500
+8850
+5%
90%
19
+2500
+13k
+5%
95%
20
+5000
+19.5k
+5%
100%
21
+5000
+29.5k
+25%
125%
22
+5000
+44.5k
+25%
150%
23
+25%
175%
24
+25%
200%
25
+10k
+150k
+25%
225%
26
+25k
+225k
+25%
250%
25k
Note: Since the Hero XP increase are the same for Forge level 14 as for Barrack of same level I think this column maybe are the same for these two type of buildings or maybe even for all buildings. The numbers in this column are copied from the Barracks page and not verified!
