steal weapon?

what weapon do you need to learn steal weapon and how do you get it.my theif is lv.25 and i think i have all the abilities for it but that.

The Sword Breaker has the Steal Weapon ability. It's a 300 AP ability. You get it from some higher level missions (it's random), from beating random clans (also random), or from trading/trade goods. You can't buy it, and there is no mission that is guaranteed to give it to you.

Sword breaker is not always readily available, so sometimes you have to find ways around it. You can steal the Steal:weapon ability from certain missions, if that pleases you. I'm assuming you already know the Steal: ability... ability-_-. With that, you can steal the steal:weapon ability from enemies in any or all of these missions/clan encounters:

Clan encounters:
Tubola Bandits (Tubola)
Ramble Band (Deti)

Missions:
---Help Tubola!
---Help Deti!
027 Wanted (Draghilev Godeye)
076 Fire Sigil
016 The Big Find
059 Sketchy Thief
--- Reconciliation

[Edit]: If you DON'T have the Steal Ability... errr... ability. x_x You can get it from the Cinqueda. The Cinquedea is awarded when you raise your negotiate skill level to 30. Also, you can get the cinquedea by stealing it in mission 009 (Magic Wood), but you could only do that if you can already steal weapons. ... -_- Hrm... Anyway, most people (cheaters like me :P) get the cinquedea early in the game by kicking out all but four team members and completing the " Wanted" missions that appear over and over in the pub afterwards. Eventually, your negotiate skill level will go all the way up to 30, and then you'll get a cinquedea. It's pretty simple really. You can actually do it anytime in the game - the only catch is that if you don't do it early enough, you'll miss out on a lot of weapons and equipment that you can only get by stealing them in certain missions. Some of them suck, but if you're like me, you want to get every bit of equipment there is, so you do it the hard way and fight roaming clans for money to do the wanted missions. It takes a while, but it's doable. Then everything else is a piece of cake, and you can get some really good abilities early in the game without even having to build them up. :P Pretty cool, ne?

thank you that helps a lot.

Thanks for supplying that extra info. I was simply answering the question directly, by saying what weapon teaches it and where to get it, but your answer will probably be more helpful since, as you said, Sword Breakers are not always readily available. (If you really want one, find a friend, and link games to activate Trade Goods at Nono's shop, then save before going into the shop and learning that new Trade Goods are avaiable [obviously, this only works if you have reached the point where Trade Goods are available, after the first Jagd mission]. Check the shop, and buy the five available items, then reload if the Sword Breaker is not among them [the first five items, which are automatically available when you first access Trade Goods, are always the same, so this trick won't work for them. You need to link to make this work]. Trade Goods are generated when you first enter the shop after linking, so if you link and save, but don't enter the shop, you can keep regenerating the items until you get the Sword Breaker. You can also get really rare items like Genji Armlets/Shields/Helms/Armor, Ribbons, Mythril Weapons [which teach Combo Abilities], and much more this way, so it is a good method of stocking up on rare items that you may have missed or want more of)

I hope that gives you enough to get the Ability.