Not sure if this is a repeat topic. But I am gonna throw it out there anyway.
After seeing Zorro throw/slice fire out of his sword. It is apparent that each of the "Great" swords have powers. When ever he uses his one sword style each sword has a specific ability. It also appears that the sword must accept its user as its master before it will release it's technique.
This would also make perfect sense as zoro would need these moves later on to counter devil fruit users.
Wadō Ichimonji(Kuina's Sword, White Hilt) has the ability to cut anything, He calls it the breath of life. if you remember in the flashback in which he was shown breath of life that Koshiro(his master) used kuina's sword.
Sandai Kitetsu(Cursed Sword from shop owner) has the ability to "throw/slice?" fire. I forget the technique he calls it, Dragon something. I also just realized this is that Ryuuma was killed by a fire dragon while in life, he is the one who killed a dragon. man I am slow....
Anyway so my point is that each sword has a power. I have yet to even think of what his new sword's power will be but I definitely know that he is gonna kill his shadow zombie with breath of life.