Keeping a slow aura when morphing?

[Melshisedek1]

Hi. I made a trigger that cast Tornado permanent slow aura on unit to simulate fatigue. It is a corner stone of my rpg I find. I have many morphing spells and when my units morph lets say from werewolf to human, they lose their fatigue(slow aura). I need to keep this slow effect.

DO you have any suggestions. Making a trigger for each morphing would be too much, I would need eitheir an alternate spell that won't buff out on morphing or a more general trigger.

Thks