How can I make that when I reanimate a second actor the first one doesn't fall to ashes?

I would like to crate a spell which allows you to reanimate a few enemies to create a small army

Cheers

Try using a magic effect with AOE set.

Edit: I don't know another way of raising another, while the current one is "alive", without being "cancelled out".

Isn't "Twin Souls" perk supposed to do that?

You are limited to a certain number of commanded actors which is 1 by default. Twin souls accomplishes this by looking at the spell keywords and upping that limit if you cast an appropriate spell. You just need to create a perk, with a higher rank than twin souls, that always allows the commanded actor limit to be whatever max you want.

-MM

Edit: Note, if you use your own keywords you can allow yourself to summon as many of one type of creature but still be limited to 1 of other types...problem is...as soon as your summon one of those other types, ALL of your other creatures will disappear. I hate the implementation.

-MM