Suggested by iKnowledge Najimi would destroy Joker as soon as the match begins. I have a lot of respect for her character because she is an omnipotent cosmic being like The One Above All but one who actually backs up her tough talk. She is incredibly powerful and has a nice disposition as well. She’d likely just ignore Joker’s insanity and end the fight as soon as she got bored. You need more than jokes to stop her. Najimi Aijimu wins.
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I think that’s how the battle would work out. Aside from Emperor Joker, She’d have nothing to fear from him. Also, I think she’s one of the few characters on your blog who could turn him sane successfully. Jean Grey, Yami Yugi, The One Above All, Living Tribunal, Kami Tenchi, and now…Her.
Joker would definitely want to turn sane very quickly upon meeting Najimi. Otherwise he’d have to face her wrath!