Köndös is a god of swiddens mentioned by Mikael Agricola in 1551. We have no idea who this is supposed to be. This name (nor the form Köntös included in the Etymological Dictionary of Finnish) does not appear anywhere in the runosongs.
According to Agricola, "Köndös made fields and swiddens". Köndös has been seen like the personification of grain (based on things such as the Mari language word kinda "grain, bread"). Uno Harva first thought Köndös is the same as a giant named Köntys ("clumsy") who created swiddens in a Finnish fairytale. Later, he changed his mind as R.E. Nirvi pointed out that "creating" fields and swiddens can also mean sowing them—this would make Köndös the same figure as Sämpsä Pellervoinen.
Martti Haavio thought that Köndös is actually Saint Urban of Langres, or "Köynnös-Urbanus" (köynnös = "vine"). I do not believe in this at all. I am thoroughly convinced that none of the names mentioned by Agricola are references to any saints—he would've been able to tell.
The name "Köndös" is often thought to be related to kyntö "ploughing". Sämpsä is indeed described as ploughing, so that theory is not so far-fetched. I would also like to point out that Sämpsä's helper, the super-plougher, is called Vento('s) ox Uljamoinen.