If Plague rider launches his ult outside of the arcane hymn aura but walks into the aura as his ult is still going does the ult then gain he -4 magic armor and magic heal at that point or does it go by when it is casted?...in which case plague can ult while in the aura and then walk out of the aura as the ult is going?....Sorry I'm not home to test this...was just curious