Oh, in case you didn't know, Zeus has placed his protection on Hercules - any god that kills Hercules will spend eternity in Tartarus. If you forget, these lovely gods and goddesses would love to remind you:
Ares: How easily you forget, sister. Our dear half brother cannot be killed at the hand of either one of us - by order of Zeus.
Ares? Why Jason?! This is between you and me!
Ares: Because you came under Father's special protection!
Hercules: The special protection of Zeus?
Strife: No god can destroy Hercules without being fried forever by Zeus. Am I right, or am I right?
Ares: You're half-right. Obviously we can't attack him directly. But sometimes a little strife can lead to a major catastrophe.
Mother, I thought you knew. I really had no idea you cared so much about the chalice.
Hera: I want the perpetrator!
Ares: Dead? No can do. It was Hercules-- and you know how Zeus feels about little bro. Daddy's put his protection on him-- preventing us gods from killing him.
Ares: What? Am I missing something here?
Hera: Zeus made a promise to me when he made us that chalice. Anyone who takes it from its rightful place-- is condemned to death.
Then by Zeus' own words-- his protection of Hercules is off.
Hercules: What do you want?! If you're here for the chalice, just take it and leave us alone!
Ares: What I want is to see you suffer. When you grabbed Hera's chalice, you lost Daddy's protection, and now, I can destroy you.
Ares: I could have destroyed you long ago, if not for Zeus's special protection!
Strife: Ares couldn't do this sooner 'cause Zeus swore he'd smash any god who put the hurt on you! But you blew that when you stole the chalice.
(Jason and Iolaus return the Chalice, and Zeus takes away Ares's huge lightning ball)
Ares: "Nooooooooooooo! Noooooo! Why protect him again, Father?! I was so close! What about me?! I have needs!
Ares: Brothers, sister... to what do I owe the honor of being invited here, today?
Athena: You stand accused of the attempted murder - in full defiance of Zeus's protective order - of your brother, Hercules.
Athena: I suggest you take these charges a little more seriously. If this tribunal finds you guilty, you'll spend an eternity of unimaginable torment in the fiery depths of Tartarus that is reserved for fallen gods.
Ares: Sister, I'm sure you would love any excuse to put me away for an eternity. But don't you think Zeus has gone a bit far this time, protecting his little boy? I mean, prosecuting the God of War for attacking somebody... it's what I do.
Ares: I didn't... I did not try to kill you, okay? I mean, I'd love to, right here, right now... but I'm no fool. You're under Zeus's protection, and I do not intend to spend the rest of eternity in Tartarus being gnawed on by some idiotic monster. You got that, mister?
Athena: Strife and Discord... for conspiring to murder a protected mortal and for impersonating a god, we sentence you to eternity in the depths of Tartarus.
Jason: Hera hasn't told her that you fall under Zeus's protection.
Iolaus: Yeah, she doesn't know that if she lays a finger on you, Zeus zaps her for good.
Nemesis: You do know that if you harm Hercules, you'll have to deal with his father, Zeus? I don't suppose Hera mentioned that.
Morpheus: Ah, even if he does try to rescue his friends, you can't mess with him, physically. Zeus's protection order and all.
Hercules: You wanna know why he needs you? Because of Zeus's protection order. Any god that kills me goes straight to Tartarus, alright? He's too chicken to do it himself; that's where you come in. Trust me, he's just scared of Daddy.
If it wasn't for Zeus's stupid protection order - Ares cut off the thought. Zeus had put Hercules under his special protection: No Olympian god was allowed to harm a hair on his little head. And even without the order, gods didn't kill other gods. That was the sort of thing that would set a nasty precedent.