What is virpiranta?

Some articles on virpiranta:

Efnysien - Character Analysis
... Mika Virpiranta interprets Gwern's sacrifice as symbolic, i.e ... According to Virpiranta, the reason why this retriggered an onslaught was that Irish did not approve when their prince was kidnapped for the Sun cult ... Thus Virpiranta sees Efnisien as a Sun god and therefore the Welsh equivalent to Esus ...