The Deathknight Order

From the introduction:

Ages past, a less known death knight was created. His story wasn't as tragic as some of his most famous brethren, nor his deeds of evil so grand as to give him a place in the tomes of knowledge. That was because this death knight who went by the name of Nikodemus was at heart a philosopher. Decades of unlife gave him enough time to ponder and accept his new life as another form of existence. He then spent an equal amount of time traveling the realms in disguise, debating with thinkers and all kinds of philosophers of the mortal races about the undeath.