If I may interject for just a moment? Do we know what happened to Kagrenac's tools after Morrowind? I've never finished the game myself, but I would assume the Nerevarine either kept them or they were destroyed. Any thoughts?
My Nerevarine took it with him to Mournhold and later to Solsthiem. I assume the Nerevarine took the Tools with him/her to Akavir when he/she went, or perhaps left them with someone trustworthy like Divayth Fyr.
Besides their primary usage of enchanting or disenchanting the Heart of Lorkhan and tapping into said power, the gauntlet has powerful buffs and so do both weapons. Keening and Sunder are two of the most lethal weapons in all of Tamriel, surpassed by almost none, and considering their relatively low weight, high attack speed and battle magics, I would consider them to be THE very best weapons of all. I doubt the Nerevarine would leave these tools behind on an expedition to Akavir.
My prediction is either the Neravarine is alive and is wearing them, or they're in Tosh Raka's belly - or perhaps the Tsaeci killed the Nerevarine and intend to use the Tools against Tosh Raka. Perhaps it would be possible to undo the enchantment that made him a dragon in the same way it was possible to disenchant the Heart of Lorkhan....
edit: Now that I think of it, if we assume the Neravarine kept and uses all the major artifacts aquired during the events of Morrowind alone, not to mention Bloodmoon and Tribunal, he/she should be almost completely invincible. I don't have time to do the math right now but tallying up the enchantments from all the rings and amulets the Ash Vampires drop, and the Robe of the Hortator, and Wraithguard, and any number of other items likely collected during the main quest, I'm pretty sure the Nerevarine would be walking around with over 100% resistances to certain types of attacks at all times. Tosh Raka eat your heart out, big boy! What's fire gonna do against that?