Yes but anything so powerful will have weakening effects or other side effects.
No, why would this be the case for one of the world's most powerful artifacts?
The only drawback seems to be what was explicitly stated. that it can only mind control 1 person at a time. Which the king explains why he doesn't use it on someone else. were he to do so, MC will be freed until he can switch control back to the MC. giving the MC a window of opportunity to escape.
He should continue to try to resist it.. I expect that is why he is having all the headaches.. he keeps resisting it and he gets into such a state they will have to stop using it so much. The thing is fight it.. don't just let it control you.. he never sounds like he is trying to resist it at all.. I feel it coming on.. than bam.. no trying to resist it at all.
He is trying to control the way he acts. As he feels it is about to turn him into a puppet trapped in his own body. By fulfilling the exact command before the puppetting stage, it allows the MC leeway in the exact methods of execution of the orders.
Specifically, it allows him to be gentle towards the girls and not violently rape them.
Second he never even tries to escape. Try making me a damn prisoner and I'm going to try every method to escape if that means climbing down the damn wall and risk falling to my death.. Anything to make them realize it's no so damn easy to control me! In RL I would rather be dead than a slave.
He is not in an apartment building, he is in a castle. with guards. and windows that are too small to fit through.
Also, again, literally mind control. He does not have the option to escape or commit suicide.
IIRC he was explicitly ordered not to.
This is also why the king holding him hostage explicitly notes that if he were to use the eye on someone else, the MC might escape in the time he is not mind controlled.
Also, it is pretty stupid to commit suicide after 6 weeks of captivity when you know you are backed by enormously powerful people (2 queens, one king, and a powerful nation) who will rescue you soon. The MC has children and wives to consider the well being of.
Aside from that, he is a magical beacon revealing his exact location at all times. the longer he is alive, the more exposed his captors are to retaliations.
Spite would dictate you stay alive and reveal the location of the enemy headquarters
I would go by that to use the eye is draining to the user so I would make sure that he damn well has to control me 24/7 so that it would wear and eventually break that asshole down mentally! Never make it fucking easy for evil ones.
And then you will kill everyone with your sick katana skills. single handedly slaughtering entire armies.
while farting lightning.
/sarcasm