Class and Level Geekery VIII (spoilers ahoy!)

[Winter]

Malack describes Nergal as a god of Death and Destruction; in the absence of any other evidence I'd guess those were his domains.

Gods usually offer like five domains (or so). Being God of X and Y does not mean a cleric can only pick those. Depending on what Nergal stands for, he might even sport protection, war, chaos, law, evil, ...

It's not that Selûne in the Forgotten Realms only allows "Moon" and "Travel" as domains... gods usually at least feature their [aligment] (if good or evil, lawful or chaotic).