I like "Serens", but there's a certain charm to "Serenwildebeests".

Serenwilde is anything that's not really directed. The forest "Serenwilde is beautiful." The people "Serenwilde is a frienldy community."

Seren is more directed, such as your example. "I love the smell of the Seren in the morning." Or "The Seren are friendly people."

There're all proper nouns and can be used in any of those sentences if placed with the right adverbs or adjectives.

Hehe.

I'll try at these...Gaudiguch: Gaudigans (assuming 'uch' can be interpreted as just a city suffix, perhaps even 'guch', but Gaudians sounds weird). Hallifax: Hallifans?

You're right, they are too abstract.

I'd probably go with Gaudiguchi for Gaudiguch. From what I've seen of Gaudiguchi names in the history, some of them seem to like ending names with 'I' sounds (Scuchi, Iborchi etc.) Maybe it's just me.

Hallifax has me stumped though. Hallifactoids?

Hallies.
Hallies! To arms!

Throughout history Seren has just been an abbreviation of Serenwilde. Although I do understand the problem with differentiating Serenwilde the organisation and Serenwilde the forest.

Hmm..

Hallifax: Hallians?
Gaudiguch: the Gaudi(Gawd-eye)

Hallifaxi
Gaudiguchans
Magnagorans
Serenwilders
Fishboys/girls, dead, Celedogs or Target all work fine

Hallifax - Faxians
Gaudiguch - Guchi

as possible shorter versions.

Regardless of what Serenwilde says, Serenwilders are Serenwilders to me, and Magnagorans are generally referred to as Tainted or Mags in a hurry though I do often call them Magnagoran when I've got the time to spare to write it out. Celestians for Celest citizens.

Magnagora: Dom
New Celest: Sub/The Spanked

:-P

serens/serenwilders, and city-scum

Meh, I personally call my fellow people from the Serenwilde Serens.

I was always a fan of

Serenwilde: Serenwilders
Magnagora: Magnagorans
Celest: New Celestians

But that last one is because Ibsen is always happy to point out that the old empire still lives, its now a land of taint and death, but it still stands. Spectre island is also Old Celest by this system