Any NPC with a relationship value [disposition] of 1, 2, or 4
[friend, confidant or lover] will power up the blade when slain with
- UESP wiki, on the Ebony Blade
Here's what I do to power it up, without getting any of the regular named NPCs killed:
I murder* multiple clones of my spouse (through the
player.placeatme <object/base ID> console command) to power up the Ebony Blade. Each time you enter the
player.placeatme <object/base ID> console command, you spawn one copy of the NPC whose object/base ID you have targeted.
This should work even with non-spouse, killable (non-essential) NPCs, as long as they are a friend, confidant or lover. To know an NPC's disposition towards you, use the
getrelationshiprank player (while NPC is targeted) or
player.getrelationshiprank <target NPC refID> console commands. All spouses are lovers, that's why I'm sure that their clone's deaths will power up the Ebony Blade.
It is best to spawn clones of the person you want to murder in a secluded area where no one else will see you and the clones (to avoid bounties and other NPCs ganging up on you upon witnessing you murdering someone). I prefer doing it in the testing area myself, where no NPC ever goes to. You can go there using the
coc qasmoke console command. (You can also use the
coc <cellname> console command to get out of the testing area.)
* HAIL SITHIS! (and Mephala, too)