Two ships had arrived in Gaster Kingdom a month ago [January], but these ships weren't there to bring gold or deliver products and last but not least they don't belong to Gaster Kingdom.
If you can remember it, a couple of months ago King Zar ordered two medium sized ships from the Zamerians. These ships, will be used to transport either food or Guards all the way across [Country] Orientis Ignis to form what King Zar calls the greatest military move yet, an Outpost.
Frozen Toe Kingdom doesn't have any people living in it any longer, so it proves useful as an outpost. As specified before, the intent of this Outpost is to cause military suppression towards the illustratian Alliance, specifically any nearby domain in the Country below them, Meridionali Ignis.
One of these ships can carry a whole platoon [100 Guards] easily since it is a medium sized ships. Hell, Lav Kingdom used two of these ships to transport 500 people so it can obviously fit one Platoon with ease.