PetrusOctavianus: From the author of the mod:
"What UB does to Kagain's quest is the following:
-adds the body of the boy to the area "CoastWay" with the caravan
-Makes Kagain notice and comment the body as you already mentioned.
That's it. It's the dialogue that is in Kagain's dlg file which wasn't used in the game, so UB made it available."
Kagain should make a comment about his reputation being in the mud when he finds the dead son of Duke Entar Silvershield. I think you also find a family heirloom or else the heirloom is just there to identify the dead boy as a Silveshield.
UB does very little to Kagain and his quest. It doesn't do anything to the Silvershields in Baldur's Gate for example, so Kagain's quest is at en end when you find the dead boy.
IIRC there is also a time limit. If you wait too long to find the caravan you won't find the the dead boy.
You can use the heirloom to get into the family home in bg... a certain bard npc wants to go there to see/ collect his gf.