For whatever reason, the author's chosen to give all the characters names in Finnish.
Valtava means "Huge".

Bicorn said:

For whatever reason, the author's chosen to give all the characters names in Finnish.
Valtava means "Huge".

Fantasy cultures are often counterparts to IRL cultures. Maybe the local culture in this setting is based on Finland.

I'm guessing it's a bit late to be posting this, but I just started thinking that the name "Lina" might be a bit wrong.
Based on the reading it would be "Riina," which in finnish is a more common name than either "Lina" or "Liina" combined, though they are also valid finnish names.

At this point it's probably too much of a hassle to change the name in all of the notes, and also we don't know the exact intention of the author. Just thought it might be worth mentioning.

For reference: http://verkkopalvelu.vrk.fi/Nimipalvelu/default.asp?L=3 a database of finnish names as well as popularity in certain periods.