helvetene is the neuter plural definite of helvete.

helveteN

Kven

helvettiN; hiisiN

Norwegian Bokmål – Kvendict-nob-fkv/src/N_nobfkv.xml:24800Edit on GitHub Suggest

hiidaN; helvetN

Norsk-nordsamisk ordbokdict-nob-sme/src/N_nobsme.xml:26951Edit on GitHub Suggest

Case	Sg	Pl
Indef	helvete	helveter
Def	helvetet	helvetene