Do either of them solo the heralds as tyrant did or do they both go down? They don't fight together.. they each try and replicate what Tyrant did.. Can either?
That hammer toss by BRB would most definitely get their attention. DS goes down, Thanos muscles through. Not as easily as Tyrant did, but he gets the job done irregardless.
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.
The total roster at once: Surfer/Gladiator/Ganymede/Morg/Terrax/Jack of Hearts/Legacy/BRB could potentially pose a threat working in tandem but I think Thanos and Darkseid get the job done.
Fighting individually, they both lose; Thanos had to protect himself with Terrax's axe when fighting Morg solo, with all the other heralds backing Morg up, Thanos gets ripped apart...