The following is a listing of all unique weapons know in ROSE online. Using
http://rose.zenno.info/ as a guide, I translated the parts google left behind, thus completing an English guide. Thank me later

Some English names may not be completely correct, as this has been done through direct translation.
AP = Attack Power
Req = Requirement
WS = Weapon Speed
ASPD = Attack Speed
DEF = defense
One Handed Swords
Falchion - AP 47, Req STR 96, WS +4, Bonus HP +300, Drop from Crawfi King
Gladius - AP 98, Req STR 147, WS +4, Bonus AP +30, Drop from Grand Master Golem
Filangi - AP 135, Req 183, WS +4, Bonus MP Reduction 20%, Drop from Tyrant
Two Hand Swords
Tsuvai - AP 78, Req 97, WS +2, Bonus Crit +35, Drop from Grunter King or Crawfi King
Pheonix - AP 104, Req 156, WS +2, Bonus MP Reduction 20%, Drop from Grand Master Golem
Dual Swords
Falchion & Gladius - AP 97, Req DEX 84, WS +2, Bonus AVO +25, Drop from Guardian Tree, Grunter King, or Crawfi King
Falchion & Filangi - AP 157, Req DEX 122, WS +2, Bonus ASPD +20, Drop from Tyrant
Filangi & Filangi - AP 209, Req DEX 154, WS +2, Bonus AP +30, Drop from Behemoth King (thats what's listed)
Blunts
Gurz - AP 67, Req STR 117, WS +3, Bonus HP +400, Drop from Grunter King or Crawfi King
Spike Club - AP 126, Req STR 171, WS +3, Bonus Crit +40, Drop from Grand Master Golem
Two Hand Ax
Devil Ax - AP 98, Req STR 123, WS +1, Bonus HP +400, Drop from Grunter King or Crawfi King
Dark Buster - AP 120, Req STR 181, WS +1, Bonus DEF +60, Drop from Grand Master Golem
Spears
Glaive - AP 106, Req STR 125, WS +3, Bonus Crit +40, Drop from Crawfi King
Bastard Spear - AP 166, Req STR 176, WS +3, Bonus AVO +30, Drop from (unknown)
Katars
Zamadar - AP 68, Req DEX 90, WS +4, Bonus Crit +35, Drop from Grunter King
Chakram - AP 87, Req DEX 139, WS +4, Bonus AVO +30, Drop from Grand Master Golem
Shining Fingers - AP 152, Req DEX 175, WS +5, Bonus AP +30, Drop from Tyrant
Bows
Bow of Fairy (Nymph's Bow) - AP 62, Req DEX 96, WS +3, Bonus AVO +25, Drop from Grunter King
Bow of Artemis - AP 116, Req DEX 134, WS +3, Bonus ASPD +20, Drop from Crawfi King
Bow of Sagittarius - AP 102, Req 163, WS +4, Bonus Crit +45, Drop from Grand Master Golem
Bow Guns not much is known about unique bow guns... cause no one cares... this section is kind of incomplete... lack of info
Shot Bow Gun - AP 118, Req STR 114, WS +3, Bonus Crit +40, Drop from (unknown)
Metal Bow Gun - AP 179, Req STR 154, WS +3, Bonus ASPD +20, Drop from (unknown)
Staves
Shining Staff - AP 57, Req INT 91, WS +3, Bonus MP Reduction 21%, Drop from Grunter King
Lunar Staff - AP 88, Req INT 138, WS +3, Bonus MP Reduction 25%, Drop from Grand Master Golem
Chronicle Staff - AP 147, Req INT 175, WS +3, Bonus MP Reduction 28%, Drop from Tyrant
Wands
Koyote Wand - AP 68, Req INT 111, WS +1, Bonus MP Reduction 13%, Drop from Grunter King
Dust Wand - AP 117, Req INT 172, WS +1, Bonus MP Reduction 17%, Drop from Grand Master Golem
Crystal Wand - AP 145, Req INT 196, WS +2, Bonus MP Reduction 20%, Drop from Tyrant
Guns
Potbelly Gun - AP 78, Req CON 93, WS +2, Bonus MP Reduction 13%, Drop from Grunter King
Sperro's Revolver - AP 119, Req CON 131, WS +2, Bonus MP +200, Drop from Crawfi King
Abyss Rifle - AP 163, Req CON 165, WS +2, Bonus ASPD +20, Drop from Behemoth King
Launchers
Gattling Launcher - AP 101, Req STR 59, WS +1, Bonus MP +200, Drop from Crawfi King
Faust - AP 155, Re STR 84, WS +1, Bonus ASPD +20, Drop from Grand Master Golem
Theren you have it. The APs on all these weapons are what this site reports as being the last seen. So updates of recent could have changed some values, but the important thing, the drop locations are accurate. No one really knows the % chance for drop, but assume it's pretty damn rare.