One of the Fruits Rocks wanted, IMO, was the Gomu Gomu no Mi/Nika Fruit, typically associated, along with Luffy, with the number "56"
Next chapter will be the inverse, "65", Chapter 1165.
If the other Fruit Rocks mentioned IS the Devil Fruit Loki ate after being forced to kill Harald, it would make sense for Harald to show up next chapter. I should stop doing dumb number stuff, but here I am.
Either way, I think Harald will show up soon, probably next chapter.
I've thought Harald would kill Rocks for a while, but now, I think Harald will be the one to knock Rocks' back to his sense.
Once Xebec regains his sanity, Rocks dies fighting Saturn-Imu to let his Crew/Harald escape.