I doubt you are far enough into Col. to get Blood Sword, it requires you to go through all the ranks (BGN, INT, ADV) and each one has 5 tiers (S,A,B,C,D) and each tier has 5 rounds (1,2,3,4,5) and each round requires 11 orbs (10 to get to boss, 1 to kill boss) So you need to run Colosseum like...