傭兵の大検 [youhei no daiken] or 'mercenary's greatsword' in Japanese.
Airborne Brigade

R+
Type: Greatsword, Element: -, Growth: Fast, Cost: 16
Attack: 1,780 (lv1), 5,847 (lv80), 6,332 (lv100), 6,771 (lv120), 7,147 (lv140), 7,550 (lv160)
Defense: 880 (lv1), 2,888 (lv80), 3,128 (lv100), 3,345 (lv120), 3,544 (lv140), 3,730 (lv160)
Obtain: any chest that gives this rank
R
Type: Greatsword, Element: -, Growth: Fast, Cost: 12
Attack: 1,1200 (lv1), 3,970 (lv60), 4,301 (lv75), 4,600 (lv90), 4,874 (lv105), 5,130 (lv120)
Defense: 600 (lv1), 1,973 (lv60), 2,137 (lv75), 2,286 (lv90), 2,422 (lv105), 2,550 (lv120)
Obtain: any chest that gives this rank
Category: Equipment