Thanos slapped him around something fierce. So did a severely weakened Galactus. His only feat thus far is losing. Granted he loses to high level beings but we still have no idea what he can offensively.
Tough to call.
Erads is like a herald, he just often loses to people he shouldn't when you add his powers up.
Fallen One is supposed to be a strong herald, but all he's ever done is lose, and never really showed off any skill.
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I am God's mighty fist. I am God's strength made manifest.
Sig by: Skeets, S.S, thesilverspider, Sir SKEETS Alot
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Humans are afraid of the dark.
And yet… At the same time, we’re fascinated and bewitched by it.
Maybe that’s why humans drink the darkness that is coffee.
I'm pretty sure Fallen One will be 'alive' again soon. Tenebrous drained his power, but Fallen One's energy source is universal black matter and not the Power Cosmic, so more than likely he'll either just regenerate or Thanos will revive him. I doubt he's permanently 'dead'. I doubt Morg is permanently dead either.
As for the fight, I haven't seen enough of Fallen One to say he'd beat Eradicator. Other than destroying Thanos's ship he hasn't done much but be pissed off and get slapped around by Thanos, and then he got drained by a Galactus Level being. I'd have to take Eradicator based on on-panel evidence.