1a. The Crusader's Flurry feat lets you flurry with your deity's favored weapon. This requires worshiping a deity whose favored weapon is the weapon you want to flurry with, of course.
1b. A sohei 6+ can flurry with any weapon in which the sohei has weapon training.
1c. A monk of the empty hand can flurry with any weapon, but said weapons are treated as improvised weapons with different statistics.
I'm sure there are others.
2. It is as you say--one feat, one weapon. The most common way to get lots of martial weapon proficiencies is to take a level in a class that is proficient with all martial weapons. You can also be a member of a race with built-in proficiencies (tengu gets the most bang for your buck here). If you can find a way to get the Martial Versatility feat, you can broaden your proficiency feat to encompass an entire weapon group, but that usually requires four levels of fighter (or a class whose levels count as fighter, such as brawler or warpriest).
1d. Ascetic Style + Ascetic Form. (You have to get proficiency somehow first.)
Important to note proficiency doesmt let you necessarily use it as a monk s weapon.
1d. Ascetic Style + Ascetic Form. (You have to get proficiency somehow first.)
It also needs ot be a weapon in the Monk weapon group, of which all but Tri-point double-edged Sword and Urumi are already monk weapons. Other weapons need to be modified with the Versatile Design weapon modification.
@OmniMage: Maybe it'd be best if you told us a bit about what you have in mind: 1) Core or unchained Monk? 2) What weapon are we talking about? 3) And, most importantly, why that weapon?
Reading furry of blows again, it seems that I forgot it was 2 weapon fighting. I couldn't use a two-handed weapon with it anyways.
No, that part is actually fine:
Monk Flurry of Blows: When I use flurry of blows, can I make all of the attacks with just one weapon, or do I have to use two, as implied by the ability functioning similarly to Two-Weapon Fighting?
You can make all of your attacks with a single monk weapon. Alternatively, you can replace any number of these attacks with an unarmed strike. This FAQ specifically changes a previous ruling made in the blog concerning this issue.
I was thinking of making an elven monk that uses an elven curve blade. Nothing too special. A monk can use their special weapons in their furry of blows, so I was inquiring if it was possible to make the elven curve blade (or any other weapon) a special monk weapon.
The thing is that not every method works for every weapon, which is why knowing the exact weapon is very helpful. For instance, Elven Curve Blade is no deity's favored weapon, and thus Crusader's Flurry is out.
I don't know any of the monk archetypes, so I was going with a normal monk.
Please, do never play a cMonk without archetypes! cMonk is the weakest class in the CRB, and needing to spend feats on making your stylistic choice possible really doesn't help! cMonk actually needs archetypes to function as a PC class.
First recomendation is definitely unchained Monk (unMonk), for a regular melee build, it's a way better class.cMonk does have archetypes that make it a properly functional (albeit still not very sttrong) class, but these all drastically alter the playstyle (ranged, bard-like supporter, mounted, grappler). Melee based cMonk should still take archetypes, of course, and ever single cMonk ever must take the Qinggong archetype (which stacks with every other archetype).
The problem is, the Ascetic Form route for Elven Cursve Blade takes four feats (Exotic Weapon Proficiency, Weapon Focus, Ascetic Style, Ascetic Form), so would only come online at 7th level the earliest, or 9th if you want Weapon Finesse.
Sobei with Elven Curve Blade would also need Versatile Design (and thus a feat for proficiency), but Elven Branched Spear would work fine (and is actually better, being a reach weapon). Sohei isn't bad (especially if you want to take Weapon Finesse), especially mounted, and can wear armor, but might not be what you envisioned for a Monk. It also takes 6th levels before you can flurry with the weapon.
To be honest, I would strongly suggest using a monk weapon instead. UnMonk is proficient with all monk weapons (i.e. all weapons with the monk special quality), and there are so many really cool weapons that you should be able to find something that feels elvish enough. One of the elven deities (Findeladlara) has quarterstaff as a favored weapon, for instance.
Maybe the curve blade is too much. Perhaps I should scale back to longsword or something. I'm trying have the elven background influence the class.
For Ascetic Form it doesn't make a difference, but longsword can be used with Crusader's Flurry. That requires you to worship a non-elven deity, though - I personally feel that worshiping a elven deity and wielding a non-elven weapon is more "elvish" than the other way around.