User blog comment:Bluestripethewild/Sneak peek of The Power Of The Modnar/@comment-1426944-20090912015214

He killed Groddil for a number of reasons. firstly, If groddil had gathered the new horde, He would have defeated Salamandastron, which would stop many wars in the future, Saving many more lives. second, he wanted to test his powers more, which he haddent used for a long time. third, he just likes killing stupid people.

As for his helping Drufo, well, he just hates Pure Ferrets, so By helping Drufo, he allowed Triss to go free and eventually kill the last pure ferrets. also, by helping Drufo, he also killed Drufo, who died trying to help Triss. It also makes his true meanings more mysterious.