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[Marvel] Exactly how powerful is Ghost Rider when Johnny Blaze loses control?

I remember in the "Ghost Rider World War Hulk" comics, Dr. Strange saying he could have beat Hulk but there was nothing to avenge, so he didn't. So what I'm wondering is just how strong can he get?
gpt
The Ghost Rider also known as Johnny Blaze is a human soul melded with Zarathos, a third tier demon. This means in the ranks of demonic beings he is three steps removed from the Adversary himself, opposition to the christian God and possibly the enemy of the One-Above-All, two steps removed from malevolent Elder Gods, and one step beneath Hell-Lords. He is above lesser demons, minions, and summoned evil souls and such.

When free of Johnny Blaze's control, the Ghost Rider has all the powers and abilities of a malevolent quasi-mystical spirit which can survive and thrive in the deepest of Hell dimensions, empowered with fire that can burn the very soul of a victim, and a special ability unique to Zarathos, the ability to stare into any sentient being with a soul's eyes and show them all the misery they've ever inflicted on any other sentient being.

This 'Penance Stare' can be quite effective- imagine if you're a being such as Galactus who has inflicted misery on uncounted billions of souls, what would you experience when Zarathos stares into you?

The stare aside, very few creatures can stand up to the hellfire he emits as a matter of course, as even the strongest of invulnerability doesn't extend to one's soul. 

Demons are powered by direct worship, consumed souls of other sentient creatures, or humans' sense of negative emotions (in Zarathos's case, remorse and guilt), and most demons have a domain in which they wield power. In that domain they have the accumulated spiritual energy inside them of every human that sincerely believes that demons exist and suffer from whatever affliction they represent, and can convert that energy into physical strength and toughness at will.

Outside their domains their power is significantly limited, usually to the pool of beings that actually directly worship them and willingly grant them power, or to souls that they have stolen somehow and converted into spiritual energy. This means they can find themselves easily defeated by beings with enough raw personal power.

In Zarathos' case, His domain is vengeance- if someone is guilty of purposefully hurting other living sentient beings, Johnny Blaze as Ghost Rider will defeat them and show them the stare- if the person is good enough to feel remorse they will likely live and repent their evil ways. 

Some souls are so bereft of any good traits that the stare kills them. Their soul can't take the weight of guilt and their body gives out- they die screaming,and since Johnny will not let Zarathos eat souls, the victim's spirit will go to whatever fate awaits them- usually an unpleasant one.

Zarathos unleashed, however, will likely burn the victim's soul until his wrath is satisfied and then consume it greedily. He has no concern for his level of cruelty, as he is only giving back to the victim what the victim has already handed out to others.

If the issue isn't about vengeance? It will be no picnic, but if you are on the level of the Green Scar Hulk and such you can defeat him. Lesser beings will learn their folly rather quickly, as combating demons in straight-up combat is not a thing even experienced powerful entities do lightly.