Garthanos
Arcadian Knight
In 4e you would make the corruption a disease track LOLOne thing I have noticed listening to Fellowship is that the greatest danger from Tolkien's perspective is corruptibility. There are many examples in the recounting of the legends of the past of great heroes making terrible mistakes, and the wisest and most powerful of the good guys themselves fear their own corruption. In fact, the only reason Frodo is chosen as Ringbearer is that he (and hobbits in general, apparently) can resist the corrupting power of the Ring longer.
I'm not sure exactly how you translate that to a TTRPG, but it seems important.