Trecherous Bond

Treacherous Bond has a casting value of 5.
If successfully cast, pick 1 friendly TZEENTCH
MORTAL unit wholly within 9" of the caster
and visible to them. Until your next hero phase,
roll a dice before you allocate any wounds or
mortal wounds to the caster. On a 3+, you must
allocate those wounds or mortal wounds to that
friendly unit instead.