Nice to see the new spells, i feel like you should still be able to move around during the counter animation but that's just me, cant wait for the next update
You get it by going out of the tower, interacting with the glowing red circle thing and then going down into the cave where you'll find a purple portal, open that and you can find these blue slime guys that give you mana when you capture them.
Edit:Being completely honest, i thought that you werent going to come back to that, but im happy that what i said legitamately made you look back onto it, good luck with the coding and whatnot