Why is my Shadowfiend a Lightspawn?

Classes Priest
1

I thought I could have used Glyph of the Lightspawn in the past but when I try Vanishing Powder it says that I have no active glyphs. Is it maybe because I selected Oracle in the talent tree? I wish to go back to having a Shadowfiend… possibly without having to switch hero talents or spec.

EDIT: moved to the General Discussion forum, please reply there if you wish to.

2

Same was with Glyph of Sha for years now. Defaulted on my Discipline spec, can change to Lightspawn only, no standart version is allowed