From Lineage 2 Encyclopaedia

Properties

Curse Weakness
Decreases the enemy's P. Atk. by 17% for 30 seconds.
Class	Spellsinger
Type	debuff
Attribute	-
Recast time	2 s
Cast time	1.5 s
Cast range	600
Classes with same skill	Human Mystic, Wizard, Sorcerer, Necromancer, Warlock, Cleric, Bishop, Prophet, Elven Mystic, Elven Wizard, Spellsinger, Elemental Summoner, Elven Oracle, Elven Elder, Archmage, Soultaker, Arcana Lord, Cardinal, Hierophant, Mystic Muse, Elemental Master, Evas Saint

Skill Upgrade

Lvl. to Learn	Skill Lvl.	Description	MP Consume	HP Consume	SP
14	1	Decreases the enemy's P. Atk. by 17% for 30 seconds.	3	0	2
20	2	Decreases the enemy's P. Atk. by 20% for 30 seconds.	10	0	4
25	3	Decreases the enemy's P. Atk. by 20% for 30 seconds.	12	0	6
30	4	Decreases the enemy's P. Atk. by 20% for 30 seconds.	14	0	9
35	5	Decreases the enemy's P. Atk. by 20% for 30 seconds.	15	0	11
40	6	Decreases the enemy's P. Atk. by 23% for 30 seconds.	35	0	30
44	7	Decreases the enemy's P. Atk. by 23% for 30 seconds.	39	0	37
48	8	Decreases the enemy's P. Atk. by 23% for 30 seconds.	44	0	67
52	9	Decreases the enemy's P. Atk. by 23% for 30 seconds.	48	0	96
56	10	Decreases the enemy's P. Atk. by 23% for 30 seconds.	52	0	105
58	11	Decreases the enemy's P. Atk. by 23% for 30 seconds.	54	0	121
60	12	Decreases the enemy's P. Atk. by 23% for 30 seconds.	55	0	151
62	13	Decreases the enemy's P. Atk. by 23% for 30 seconds.	58	0	200
64	14	Decreases the enemy's P. Atk. by 23% for 30 seconds.	60	0	210
66	15	Decreases the enemy's P. Atk. by 23% for 30 seconds.	62	0	310
68	16	Decreases the enemy's P. Atk. by 23% for 30 seconds.	64	0	478
70	17	Decreases the enemy's P. Atk. by 23% for 30 seconds.	65	0	711
72	18	Decreases the enemy's P. Atk. by 23% for 30 seconds.	67	0	748
74	19	Decreases the enemy's P. Atk. by 23% for 30 seconds.	69	0	1000