"You are Scared" "I'm not"

Yeah, the basic concept of the magic circle was really simple. However, making that simple concept work was hard in itself. First of all, the spell requires a hell lot of mana to activate. 

And this is not any standard type of mana intake, in this spell the more people you will teleport and the longer the distance will be, the more mana it will take. Similarly, it goes the other way around too. 

For example, if you were to teleport 100 people to a distance of a thousand miles, it would require an enormous amount of mana. But if you had to teleport an insect to a distance of only a decimeter or so, the amount of mana required would be more or less the same. 

This was one of those spells where you were bound to expend a great amount of mana unless you are teleporting the right amount of people at the right distance. Finding that 'right scale' was kinda hard if not impossible, but even if I did find it out it wasn't going to be of any use to me.