The actual, historical Apostles of Linnaeus were a group of students who carried out botanical and zoological expeditions throughout the world that were either devised or approved by botanist Carl Linnaeus (Carl von Linné). It’s quite unlikely that any of them are alive within the timeframe of Vaesen, but I simply think they are too interesting to ignore. But how should they (or their legacies) be used in mythic Scandinavia? Well, here are a couple of ideas:
1. They all wrote books and had book collections of their own. Some could very likely be found in Upsala, or in other Scandinavian locations. Most of Apostles were Swedish, but not all. Descendants could be found basicly in any place in the world.
2. Although the Apostles are all dead, there are living descendants. They might be powerful NPCs or even PCs. It’s likely that they would have some connection to Upsala.
3. The fact that the Apostles travelled the world means that they could have brought very exotic creatures and/or plants to Scandinavia. Or at least described them in a book or two. Their descendants might also have international connections, and interesting map collections, perhaps with secret maps. It could be a starting point for expeditions outside Scandinavia.
4. Some of the Apostles lived in Upsala, while others didn’t. Visiting these places could be cruisal in terms of contacts and knowledge. They might also have knowledge about the HQ in Upsala.
5. It would make sense if some (or even all) of the Apostles and/or their descendants had something to do with backstory of The Society. Some of them might even have formed their own societies.
It’s quite easy to find information about the Apostles. Many of them are described in individual Wikipedia articles. You could start here: https://en.m.wikipedia.org/wiki/Apostles_of_Linnaeus