This was all because a wife was needed for LLEU as his mother ARIANRHOD was adamant her son could not marry a mortal. However BLODEUEDD turned out to be flighty and not very nice with it. She found a lordly lover and together they plotted to kill LLEU.
This was no easy task as LLEU could only be killed with a spear that took a year to make, and then only if he was standing with one foot on a goat or some other edible animal and the other on a bath tub edge. This takes some serious planning.
The would-be assassins almost pulled it off, but at the crucial moment LLEU managed to turn into an eagle and fly away.