I'm a firm believer of Itto x All and Benny x All, I just love them so much and think they deserve their harems. I've always been into the rarepair scene so like ZhongItto and Chennett were my faves. Then one day I was redoing my bio and ended up with "All x👍 All x👹" next to each other and it clicked. Why tf wasn't I shipping THEM? SO YEAHHHH- It really just began like that~ Then I began my reasons for them meeting and how well Benny, someone who found themselves outcast in Mondstadt (cuz of his bad luck), could relate to Itto, someone who was also cast out from Inazuma (cuz he's an oni)
Then because I just LIVE FOR INCEST, then I was like 'ya know, their hair looks kinda similar' and then saw how Benny always has his goggles on and went 'he totally has oni horns under those goggles' and then started this whole thing where Benny finds out he has horns when he's young, goes to the library and dreads all the books on how onis are monsters and cause havoc, and then begins to blame his bad luck on the fact that he's an oni, 'it's part of his nature'. Then eventually the traveler takes Bennett to Inazuma cuz BENNY BE ON EVERYONE'S TEAM- LET'S BE REAL, and he meets another oni for the first time, Itto. Benny sees how happy Itto is, how he's surrounded himself with people who actually appreciate him, something that Benny longs for. Sooooo he joins the Arataki gang ^^
Later on, Itto eventually introduces Benny to Granny Oni and she's stunned because she remembers Benny from when he was a baby and pulls out a picture of Itto holding a tiny little baby Benny and she tells the two that she was originally going to raise them together but one day Benny disappeared, and she didn't want to make Itto sad by telling him his baby brother was gone... BUT YEAH! Long lost brother Benny~~