Such an incredible act.
Wait, could it be the work of this Shadow Orb...
As Archelon read the soul contract book in his mind, he observed the orb that had sealed him.
This orb's scholarly name was "Shadow Imprisoning Orb," capable of locking down the target's spell casting ability, which must include the function of suppressing the Magic Heart.
It might be this very Magic Orb that prevented his Magic Heart from affecting Mental Magic.
Archelon quietly noted this down.
He read through the soul contract book several times.
Seeing that the contract spelled out the terms "obedience in exchange for freedom," Archelon felt greatly reassured.
At least until the termination of this soul contract book, he could preserve his soul.
"My Lord! I am willing to accept your contract! Please let me out so that I can sign it properly!" Archelon shouted towards the outside of the orb.
"Once you're out, behave yourself."