Nidhoggr is more connected to evil itself, then to death and/or undeath.
( You might get a Nidhogger if he ever combines evil and dragon with death tho. )
Sure there is that one part where its said to sometime eat the dead thanks to him having a lair next to the Norse mythology equivalent of the river Styx.
But other than that it has little connection to death itself.
But Nidhogger, for the most part, is just chilling on the roots of the world tree where he is eating/gnawing on the forever regrowing roots of the world tree.
Siegwurm, on the other hand, most likely takes inspiration from Siegfried the dragon slayer. (And you got to remember that Wight has the "human or person" medal in him and not just the undead/dragon. )
Siegfried himself has even less connection to death the Nidhogger has, but Siegfried's story as a whole has a lot of death in it... much more then Nidhogger ever had.
Siegfried who slays the dragon Fafnir (that himself killed his own family over a hoard of cursed gold that transformed him into a dragon) was later killed by his own friend thanks to his wife betraying him.
Not to mention one of the reasons for his betrayal was a lovers quarrel with a valkyrie ( a messenger of the dead ) who then later kills herself after Siegfried´s death.
Another thing to note is that the name "Sieg´s" meaning itself has a lot of qualities attributed to itself like victory, protection and other things that fit Wight´s personality so there is that too.
Also given that Siegwurm has
a human form, it also makes some sense to name it after a human considering the fact he used to be an undead human type monster from the start
( As a side note...IMO Fafnir would also have worked if you go down that route.. but then again Fafnir is also not a death dragon as much as he is a evil/greedy dragon )
Nidhoggr would have been a great name for sure, but it's not like Siegwurm doesn´t fit the bill as well.
replace the "wight" with "a skeleton", and the joke is even better / more accurate considering...
He gets dumped by his skeleton girlfriend after the war is over because he turned into a dragon.
( We have not actually seen his girlfriend in the manga IIRC, so they might have just removed her from the story as she was kind of unimportant outside of making really good bread)... yes you read that right... the MC makes a undead bakery because undead are free slave labour who don´t need to get paid or eat like the slave driver he is...
did i mention he makes his undead out on humans from the city after he kills them and resurects them without asking ?
Its so easy to spin the things the MC do to make him sound evil and stuff, while he is actually a really nice guy deep down... i promise he isent the evil overlord i make him out to be...
i have made a whole post in previous chapters on just a few fucked up things the MC does, but the reason he does them is for good reasons.
But I digress, back on topic about Wight´s love life...
wight later on gets married and has a child with another character we actually have seen.
don´t ask me how a undead can have a kid with a living creature... it just works
I like fucked up power ups that at least try to explain themselves. And i am somewhat satisfied from the explanation. Also, i hope Procell likes chinese food, because it's roasted kitty for dinner
Hmm...on one hand, I swore to drop this if Wight died, and that DID happen, but on the other hand he turned into a dragon, and always be a dragon, so I’m going to call that a net positive and keep reading.
I was thinking a bone dragon as well, and worried about his girlfriend.
It might be the first time I've regretted opening a Spoiler tag. She did show up in a frame, it was a skeleton with a flower on it's head, but I don't think anything else showed up.
I’m disappointed they just made him a normal dragon. I was expecting a dracolich or something. They could have at least given him bony plates or something.