Ludwieg the tall and Irena marching for revenge

This is a sad story.
Ludvieg and Irena were rulers of a Nordic province when they were promise a benediction by a visiting ally ruler, the Mage Sativi.
The spell promised to make Ludvieg and his ride the strongest of the land while giving Irena the lightness and swiftness of a bird. Everything worked well until the Mage headed back home. The spell then turned odd and its effect took a literal meaning, up-sizing one over the limits of human and turning the other to a dark, short lived crow.
They raised troops and are now blindly heading for revenge, even though some warned that this could reveal a well organized trap.