If we up Exitar to the level the Merged Celestials showed (which ever since I seen it, it seems like an explanation for Exitar's girth), then he one shots everyone in this thread.
Team wins though even if he isn't that powerful though based on what we've seen. Galactus supposedly beat TnA (well, he did, but we never seen it). Weakened Galactus got beat by a cheapshot while holding his own against Tenebrous. A hungry Galactus Galactus stomped a mudhole in Sphinx. Exitar killed the most powerful Watcher.
And Arishem jams his thumb up someone's anus.