Can You Mix Spells?

Yes you can, you need to be more specific for anyone to help you though

what do you mean "mix"

Perhaps you could do it this way (no idea if it works, just a thought, e.g. with endurance aura and critical strike)

1. You give the hero both abilities (but you remove the icon of one of the abilities so it's not shown and can't be clicked, in our case lets say critical strike icon is removed)

2. You use a trigger that runs if the hero learns an ability, checks if the learned ability is endurance aura (the one having an icon) and if it's true, let the hero learn the critical strike ability (but I think there can be problems with the abilitiy-level)

3. Or you use 3 not-hero critical strike abilities (without icon) and, if the hero learns endurance aura, give the hero the critical strike ability concerning to the level of endurance aura

give the caster critical strike ability then make a dummy unit with endurance.
and create the dummy unit every 2 seconds at position of caster [give the dummy a 3 second expiration timer]

TADA: you have both in one.

HEY LUKE

HEY LUKE ITS ME you fool he means combine spells so that you only need one spell on your hero and it makes then have both like having

----- Storm bolt but it also has a chance to stun like doing BASH

Luke i could not get our account to work at schol so i made a new one

hmmmm..... y dont jus make when hero learns a skill, skill equal to endurance aura, then do add ability critical strike or something like that. if u wanna level the spell jus do remove critical strike and add critical strike 2... but kinda troublesome actually =P

Check out Darky's Multi-Aura; it might work in this case.

~The_Raven