So Kled's Q&A's Going on, and apparently yordles "manifest"
{quoted} 5. Yordle lore -- incoming soon i believe. Yordles are attracted to Runeterra cultures and enjoy manifesting around certain human ideals.
For context WAAARGHbobo is the principle writer for Kled, and his past works include Jhin, Illaoi, Tahm Kench and Rek'Sai.
Now this little lore nuggets gives us some insight in to how yordles work; being potentially not wholly physical entities, but one thing I do wanna point out is that this explains why Tahm hates yordle kind: demons embody the vices of mankind, while yordles embody human ideals. Vices versus virtues essentially. This essentially makes demons and yordles diametrically opposed entities.
Also if yordles are non physical at least some of the time, then them having special means of travelling around Runeterra, as was described by the new little "Did you know" things that appear in your loading screens, make sense; yordles go non physical and find pathways that exist only to beings like themselves.
Also yordle lore incoming. HYPEEEEEEEEEEEEEEE.
So, thoughts?
EDIT: Another dollop from the mad man himself -
Well observed. Yordle Lore coming soonish I believe (#no_idea_of_release_date --Might be a while) Yordles are magical creatures-- like fairies or --OMITED NAME (coming soon!)--- . They interact with the physical world and manifest in peculiar ways. So how YOU would see them is quite different compared to how a child or Garen might. Even Lux would see Kled slightly differently than her brother does because her relationship with magic and that heroic ideal is different than Garen's.