Guild Wars 2

Well “hins nyja Mana” does mean exactly “of the new Moon” so that would be fine, a lot of letters so maybe the whole name doesn’t fit.

Icelandic can be tricky but the straight word for word translation could be

[CharName] of the new moon = [CharName] nýja mánans

So nýja is new and máni is moon, now you could make something different like:

[CharName] hins nýja mána, which is roughly “of the new moon” and sounds a little better in icelandic.

And if you want it to be Máni the one who guides the moons in Ásatrú you would of course write it with a capital letter, while máni would be just the Icelandic word for moon. Perhabs you should also not use the special Icelandic letters ý & á since it might confuse people