1. XOverd
2. Forge

To evolve a weapon, you must combine the base weapon you want to evolve with a 0-star (0★) weapon of the same name. To get the highest evolved weapon, you will need three copies of the same name weapon, like this: 0★+0★=1★, then 1★+0★=2★.

To get the strongest weapon you must max out the level of every weapon (base weapon and consumed weapon) used in evolution. You can never regain the lost attack power from failing to use max-level weapons when evolving. If the evolution prompt tells you both weapons are contributing 10% of their attack power, then you are getting the best result.

When Evolving Weapons, the new ★ weapon will reset to level 1, but with a new, higher base attack power. In addition, the two weapons used in evolution will contribute an attack power bonus. Example:

A Sword with base attack power of 50, and a 1-★ base attack power of 60.

• Level 9 Sword, 70 attack + Level 1 Sword, 50 attack -> Level 1 Sword★ with attack power: 60 + 5% of 70 + 5% of 50 = 66 attack.
  

A max-level evolution would be:

• Max level Sword, 200 attack + Max level Sword, 200 attack -> Level 1 Sword★ with attack power: 60 + 10% of 200 + 10% of 200 = 100 attack.
  

Note: It is far more expensive in gold to upgrade weapons multiple times than all in one go!

Weapons of different rarities have different max levels:

• UC = Level 35 Max
  
• R = Level 40 Max
  
• SR = Level 45 Max
  
• SSR = Level 50 Max
  

Weapon Experience is added to a weapon when combining it with Materia or other Weapons.
For "Great Success", the experience value is multiplied by 1.5; for "Huge Success", the experience value is multiplied by 2.
Note:Experience points are truncated, so any value after the decimal place gets removed after synthesis.

Rarity	Experience/Material
	Success	Great Success	Huge Success	Increase/Level
C Materia LV1	5.5	8.25	11	0.5
UC Materia LV1	10.5	15.75	21	0.5
UC Materia LV6
UC Materia LV10
R Materia LV1	15.5	23.25	31	0.5
R Materia LV8	18
R Materia LV10	19.5
R Materia LV12	21	31.5	42	0.5
R Materia LV20	25	37.5	50	0.5
SR Materia LV1	35.5	53.25	71	0.5
SR Materia LV10	40	60	80	0.5
SR Materia LV20	45	67.5	90	0.5
SSR Materia LV1	75.5	113.25	151	0.5
SSR Materia LV50	100	150	200	0.5
C Weapon LV1	1.5	2.25	3	0.5
UC Weapon LV1	2.5	3.75	5	0.5
R Weapon LV1	5.5	8.25	11	0.5
SR Weapon LV1	20.5	30.75	41	0.5
SSR Weapon LV1	Don't know. But please don't use SSR Weapons as material.

To max each Weapon requires the following amount of experience amounts:

• C - 225 exp (which is 150 C-weapons & 15,000 gold if done in one Successful upgrade, which is impossible since Inventory only holds 50 items and at forge level 2 only allows 10 "materials" at a time to be used!)
  
• UC - 327 exp (which is ~131 UC-weapons ...)
  
• R - 507 exp (which is ~93 R-weapons ...)
  
• SR - 726 exp (which is ~36 SR-weapons ...)
  
• SSR - 948 exp (which is an unknown number of SSR-weapons for upgrades, but less than the ~47 SR-weapons needed to do it.)
  

Current LV	EXP Points		Current LV	EXP Points		Current LV	EXP Points		Current LV	EXP Points		Current LV	EXP Points
	To Next	Total		To Next	Total		To Next	Total		To Next	Total		To Next	Total
1	3	-	11	10	55	21	17	181	31	23	379	41	30	648
2	3	3	12	11	65	22	18	198	32	24	402	42	31	678
3	4	6	13	11	76	23	18	216	33	25	426	43	32	709
4	5	10	14	11	87	24	19	234	34	26	451	44	33	741
5	5	15	15	12	98	25	19	253	35	27	477	45	33	774
6	6	20	16	13	110	26	20	272	36	27	504	46	34	807
7	7	26	17	14	123	27	21	292	37	27	531	47	35	841
8	7	33	18	14	137	28	21	313	38	28	559	48	36	876
9	7	40	19	14	151	29	22	334	39	29	587	49	36	912
10			20	16	165	30	23	356	40	30	618	50		948

Note:These numbers are still a work in progress, but I think they're fairly accurate. (i.e. within 1-3 exp).