Question about Nightbringer

Already spent 50ish skeleton keys trying to farm a Nightbringer yet still no luck finding one. I don’t know if this is true but I’ve read somewhere that you can actually know if Morgoneth is holding a Nightbringer that guarantees the drop. I just want to make my runs faster without killing him if he’s not holding it. So how can I know when he’s holding the weapon?

Thanks in advance!

The normal version has two spikes at the tip

while Nightbringer has four


Thanks, mate! :+1: