from:
Mage_Wars_Official_Rules_and_Codex_Supplement_-_Updated_January_2014
Magebane
Magebane deals its damage after the spell that triggered it has been resolved. For example, when this creature casts a spell, you could reveal this at the end of the Counter Spell Step, and then at the end of Resolve Spell Step, after the spell resolves, this creature will take 1 direct damage. If the Mage destroys Magebane with a Dispel, it will still do a point of damage to him for casting the Dispel. In a duel, if a Mage casts a spell that kills the opposing Mage, and then dies due to Magebane damage, the game is a draw.
Where does this leave purify and divine reward against poisened blood?