@ubi-keo I took him down with a bow. Pretty sure I took him down with the Ravens Beak bow using the Mark of Death ability while Callin was in the midst of a throwing animation and then ragdolled beneath the road on the south bank of the Derwent River near the last tree on the right side of road right before the fork in the road that leads either further South into Eurvicscire or North into Picheringa across the Derwent River. I tried uninstalling and re-installing the game to no avail. Honestly, I think that it may have worsened the problem. My tracker now says Callin is somewhere between 140 to 160 meters below the ground. This discussion board won't allow me to upload a picture or video because the file size is too large or I lack the necessary privileges apparently. And as I said earlier I can't reload an earlier save because the autosaves have been overwritten and the last hard save was 15 hrs prior. I do not have the time or the patience to redo 15 hrs worth of progress at this time. Thanks.

He literally fell through the world after I defeated him in combat. The problem is I can't (kill him/finish him). And if I can't kill him I can't beat the game. I have tried reloading to no avail. My only other option would be to reload a hard save from 15 hrs prior. I do not have the time to redo all that progress. Any help would be appreciated. Thank you.