User blog comment:B214/Volume 23 discussion blog/@comment-1884090-20170411154430/@comment-10330822-20170412063359

Yeah, and that was what I was referencing. Personally, I want the swords to remain seperate, because it seems a little too much like Chaos Break for my tastes.

We all know one of Kiba's ultimate battles is going to be facing Arthur. So if Kiba can master Gram, it will be the ultimate demon sword vs. the ultimate holy sword, and I'd prefer that not to be sullied by the sword mixing with other swords or Kiba's SG's.

If Kiba wants to feed Gram's demonic energy through his SG, like he did for Durandal, that that's fine, and honestly, that is more like Issei's situation. Ascalon isn't completely fused in Boosted Gear, its being stored there and is connected to his gauntlet if he summons it and doesn't remove it. The advantage that sword gives is that Issei can transfer power to Boosted Gear from the sword and vise versa to combo attacks. Kiba's hypothetical "Gram Birth" would essentially be the same thing, he doesn't need to fuse the two to do that.