Here you can discuss how devil fruits work against others, for example how a fight between light and darkness would take place.
I have two questions to start with, first Blackbeard said that the Yami Yami no Mi is the most powerful one, but he was easy to hit by the fire attacks from ace so how would Blackbeard stant against Kizaru or Akainu?
And second, many asked that maybe but there was no proper answer about who would win in battle, Eneru or Kizaru.
My opinion is that these two powers match and that none of them could beat the other actually, but because eneru only knows the Kenbunshoku Haki and Kizaru the Busoshoku Haki Kizaru would be able to hurt Eneru, but what would happen if Eneru has the Bosushoku Haki or even the Haoshoku Haki?