i can’t think of any names off the top of my head that are more subtly associated with death, but here are some names with death-related meanings…
[name_m]Azrael[/name_m] / [name_m]Azriel[/name_m]
Libitina
[name_f]Morana[/name_f]
[name_m]Mortimer[/name_m]
[name_f]Tisiphone[/name_f] (maybe too tied to the Greek mythology character for a [name_m]Percy[/name_m] [name_m]Jackson[/name_m] fic)
other ones that might fit… (these are almost all poisonous plants lol 
i wasn’t sure what else to do, but i don’t know if that works well with non-violent death)
[name_f]Belladonna[/name_f]
[name_f]Dolores[/name_f] (meaning sorrows)
[name_f]Foxglove[/name_f]
[name_m]Hemlock[/name_m]
[name_f]Holly[/name_f]
[name_f]Ivy[/name_f] (like poison ivy?)
[name_f]Lilith[/name_f]
[name_f]Narcissa[/name_f] / [name_f]Narcisse[/name_f]
Nightshade
[name_m]Oleander[/name_m]