The Prose Edda on Regin
The Younger Edda: > Chapter Iv. > The Niflungs And Gjukungs.
attestation: Regin possessed the sword called Refil and fled from Fafner
"Regin had the sword called Refil. With it he fled."
attestation: Regin became smith to King Hjalprek in Thjode and undertook the fostering of Sigurd
"Regin then went to Thjode, to king Hjalprek, and became his smith. There he undertook the fostering of Sigurd (Sigfrid)"
attestation: Regin incited Sigurd to seek Fafner and the gold, explaining where the dragon lay
"Regin explained to him where Fafner was lying on the gold, and egged him on to try to get posse"