...and apperently Finnish word "Tonttu" is also a loan word "tomte" from Swedish...
...history is a messy thing... ¯\_(¬_¬)_/¯
Actually it's more likely the situation is a tiny bit more complex. The origin of the word in Swedish is "tomt", meaning a plot of land. A mythological creature looking after that lot of land was named "tomte". The bureaucratic/legal word "tomt" was borrowed into Finnish as "tontti" and then, following the Swedish example, it was turned into "tonttu", the creature taking care of the property.
Hmmm.So tiny...Is that......a human?I bring her here. No worry.If she do bad thing, I eat her.You've come to fetch the fire as well?She a Tonto.