Man that brings back memories - that was the dumbest Souls platinum to get ever.Demons Souls on PS3 is pretty famous for having a really difficult platinum because of low drop rate on certain materials.
I was lucky enough to get that platinum when they were still running pure black/pure white world tendency server events on the regular. Pretty sure I would have given up on that game otherwise. The amount of times I ran down those damned Geckos in that one large room in the Mines area... Just an awful experience.
That said, as someone who refuses to pay for console multiplayer access, getting the DS3 platinum was one giant chore as well. I must have killed thousands of silver knights for those friggin' ears.