so i searched the forums and didnt find anything about this happening to anyone else. so i cast mayhem at arcwind point, everyone begins fighting, so i cast harmony and everyone but shadowmere stops fighting, he will let me ride, but as soon as i get off, he starts attacking me, waited and spells not wearing off. anyone know how to get him to stop attacking?

Sithis wont allow his blood frenzy to be silenced! The reason I'm guessing is his level is too high.

UESP says his level is 50, while harmony only effects up to level 25. He may only be attacking you for casting an "offensive" spell on him, since mayhem also only affects things up to level 25.http://www.uesp.net/wiki/Skyrim:Frenzy

Look under notes for the reference.

im level 81 vamp with the two skill trees on the right side of illusion perk tree filled. guess ill have to reload previous save.

Casting spells at your followers can cause them to go hostile, even if you cast an otherwise helpful spell. Be careful what you cast and who is in the area.