Choosing Black Bolt as the first to fall, the Hulk brutally beat him into submission, had him fitted with a Sakaarian slave disc, and forced him to battle his fellow Illuminati.
He possesses the hypersonic scream, meaning that when he talks he unleashes a tremendously powerful blast capable of destroying planets. Even Black Bolt's whispers can cause serious destruction, as he often doesn't even speak unless the situation is absolutely dire - like the time he battled Thanos.
Finding the Inhuman city empty with only Black Bolt left, Black Bolt unleashed a powerful scream which tore down Attilan itself and activated a Terrigen Bomb which spread the Mists across the Earth. Thanos survived the attack and found Black Bolt still alive in the rubble.
The Hulk's durability wasn't able to suddenly withstand Black Bolt's scream, one of the most powerful attacks in the Marvel Universe; instead, it took on a cheap version of the power and hero and won.
In Doctor Strange 2, Black Bolt's mouth was removed by Scarlet Witch. Panicked, Black Bolt tied to speak, causing his brain to implode from the power of his own voice, which was still destructive as ever. However, Black Bolt would likely have annihilated Wanda with a single word.
Can he take on Thanos? In MCU there's no 1v1. Still Dr Strange using the Darkhold to beat Thanos when the rest of the Illuminati failed shows that Black Bolt couldn't take on Thanos. As for Marvel comics in Infinity (2013) #3, the Illuminati including Black Bolt failed miserably against Thanos.
Stopping at the Moon, the Hulk defeats Inhuman king Black Bolt. The Hulk proceeds to Manhattan, New York where he demands the presence of The Illuminati.
Wolverine has a problem taking down enemies with powerful long range attacks, and Black Bolt's voice definitely counts as one. On top of that, Black Bolt's flight gives him a way to stay out of Wolverine's range. Without back-up, Wolverine would fall before the Inhuman monarch.
The Scream symbiote was ultimately killed alongside Donna by Eddie Brock, who incapacitated it with sonic feedback and stabbed her to death with a heated knife.
As Galactus and the newly cosmic Inhuman Royal Family viscously foughtTsc it seemed that the World Eater was going to destroy the Royals, until Black Bolt released the full potential of his vocal powers, screaming "DIE!" Now that Black Bolt was a cosmic level being, his powers completely destroyed Galactus in a ...
By triggering the speech center of his brain, Black Bolt unleashes a Quasi-Sonic Scream that's capable of destroying entire planets. Black Bolt is not able to speak nor mutter any sound whatsoever; nothing will happen though if he accidentally sneezes or coughs as those actions do not trigger his speech center.
In one of the most gruesome scenes in the MCU, Black Bolt was the first to die when the Illuminati faced off against the Scarlet Witch. His powerful voice was turned against him when Wanda used her magic to erase his mouth, and Black Bolt's horrified scream blew up his own head.
When the Scarlet Witch pursues America, she is stopped by the aforementioned group of heroes. Before Black Bolt can say anything, Wanda uses her magic to remove his mouth—which results in his vocal talents obliterating his own skull.
In fact, the two heavyweights have actually squared off before, and the result was far from a tie. In DC Versus Marvel #1, Superman beat the Juggernaut with a single punch.
His adamantium claws are one of the few weapons in the Marvel Universe that can consistently pierce Hulk's skin and Wolverine has no problem going for Hulk's head. In fact, if it came down to it, Wolverine could cut Hulk's head off, ending the Hulk once and for all.
Once Cain Marko starts moving, nothing can stop him. Heroes like Spider-Man have only managed to slow down the Juggernaut, and once the villain charges, even the incredible Hulk's immense strength can't hold him back.
Who'd fit those bills? Omega level threat Inhumans would be Inhumans like Black Bolt, Unspoken and Thane. Alphas would be like the rest of the Royal family, Lash, Reader and Inferno.
