"Regina! Come to me!" Edmund yelled.
He ran to her and pulled her close.
[Fire Ring]
A ring of flames rose from the ground 1-meter radius away from Edmund's feet and spread radially across the ground. It burned the legs of the half-goblins that ran towards them, and so they withdrew from the maximum range of the fire ring.
The shorter green goblins took more damage to the entire body. Some of them got caught on fire and burned to death.
After a while, he deactivated the spell and activated a spell he crafted, a modified version of the fire ring.
[Outer Fire Ring]
A second after the fire ring was extinguished, a circle of fire appeared at the circumference of the previous fire ring.
Having the [Fire Ring] spell on would drain his mana, and so he modified the spell so that only the outside was in flames, but there was no flame in the circle.
This would reduce the rate of mana consumption.