Eurykidas DeMartos, the saga-poet, was a remembrancer during the Great Crusade and in the early days of the Horus Heresy. He had been attached to the World Eaters. 
Eurykidas is the most famous for writing the poem The Rose Watered With Blood which honored Flag-Captain Lotara Sarrin during the Great Crusade. 
The poem was largely met with derision by Lotara. 
Eurykidas died along with most of the other rembembrancers attached to the World Eaters on the order of Angron.