| Names: | Tontu 
Vesihiisi  
Vetehinen 
Veteinen
Vetheinen |
|---|
Veteinen, vetehinen or vesihiisi can refer to a maahinen which resides in water, or an illness coming from water caused by a maahinen. However, it also appears as a general term for a haltija of a body of water which might or might not be categorized under maahiset. In this article, I'll discuss veteinen, vesihiisi and haltija of water as it is understood as the spirit/deity of a specific body of water; for example, every lake has its own veteinen, and they didn't necessarily like each other.
Veteinen differs from Vellamo in that she is not tied to a specific body of water. It has been theorized that she was the original Finnish water deity, while Veteinen is loaned from Russia and Näkki is loaned from Sweden. In Karelia, Vellamo is often called Vetehinen, but Kainuian tradition makes a clear difference between them.
According to Kainuian descriptions, a veteinen is often a large dog, or a large-eyed and eared dog. It could have its stomach full of nails. It could cause bruises or even drown a person or animal in water. To avoid this, one could throw a piece of iron or a rock into the water before going in. A veteinen could not be lifted higher than where spring floods reached.
Similar to the veteinen is hetteenhaltija "haltija of a spring/quagmire", but it was smaller and turned evil if it wasn't respect properly.
See a runosong for summoning a water spirit here.
| Names: | Näkki         
Rehko |
|---|
As already established above, "Näkki" was loaned into Finnish folklore from Sweden as a kind of water spirit. It is dangerous, lying in ambush to drown swimmers, which is why you said before going to swimming: "Näkki onto land and me into water!". And vice versa when you got back up. This tradition also comes from the Swedes. At parts, the name "näkki" was connected to other water water spirits, or to Vellamo herself, as this concepts became mixed with each other in folklore. In other instances, it's even called a "water demon".
The extended Germanic folklore of Nixies playing instruments and such do not appear in Finnish runosongs.
| Veteinen, variants | From vesi "water". |
|---|---|
| Näkki | Ultimately from Proto-Germanic *nikwus "to wash". |
Only in Finnish, sorry. This is the source material.