Elder Riagán was murdered by the smooth-tongued emissary of the White Hand, subtly threatened and then killed for his refusal to concede.
'I was wrong, ${PLAYER}! You saw all -- my grandfather was a good man. How could Isengard do this? All the men were taken, and the rest murdered and wounded...and I thought Saruman was good.
'We have already asked so much of you. I do not ask you to take revenge for my grandfather. I have learned a little from him, I promise. I will not seek war, and I will not seek change. There is wisdom in the way he led us.
'My place is here now. But if your adventures happen to take you to the White Hand encampment...well, your actions are your own.'
The half-orc emissary who murdered Elder Riagán and so many others among the Stag-clan can be found in the White Hand encampment you scouted in southern Trum Dreng.
You should defeat this dangerous foe so that he may not harm another innocent person.
Chief Guto is in Lhan Tarren, taking the place of Elder Riagán.
You should tell Guto that you have avenged his grandfather and stopped this subtle and cruel division of Isengard from continuing their destructive path.