Mom said it's my turn to come up with Kai-shin headcanons today (c)
This probably isn't exactly what I'm trying to convey, but the main thing is the idea itself.
-The headcanon for the Kaioshin "space dryads" is in the same headcanon for the au! angelic dimension, considering that these headcanons were invented before the Daima- (It's very difficult to come up with and explain your idea about the smells and pheromones of space alien plants when you have congenital anosmia, but nevertheless lol)
For now, I've come across Zamasu to illustrate one idea.
Yes, kaioshin are born from apple/oak. What if Zamasu has some ivy/nettle in him, or a combination of several of these plants? Kaoishin are a hybrid of several plants, and they take advantage of this to develop their abilities. Because they are gods. For other kaioshin, this isn't dangerous, but for a mortal, it would be very painful.
Zamasu's body is covered in urushiol (the oily resin of poison ivy), and touching it stings intensely. There's also an additional effect on green skin, similar to that caused by nettles. So, Zamasu stings the skin of his interlocutor like poison ivy, and stings like nettles, which are covered in unpleasant, tiny, stinging hairs. Also, add the possibility of spreading a repulsive odor. So this might be unpleasant for the Saiyans (who will first come to Universe 10 to find out about Goku Black, and then during the battle with Zamasu and Black). Acacia? Aconite? Datura? Veratrum? The last two are poisonous if poisoning is possible.
Besides the "poisonous" smell, Zamasu, like other Kaioshins, smells like…fermented tea? They all literally smell like some kind of alcoholic beverage. But they literally subsist solely on tea/water/any available liquid that has been ingested in their bodies for millions of years; their mere presence must be mildly intoxicating or something, I don't know. Zamasu and Rumshi's first encounter didn't go well, as the hakaishin is a social elephant with overly tactile habits, while Zamasu's skin literally denies this.
-- Rumshi also moves his ears, either as a way to cool his body or as a way to communicate. Zamasu is the kind of guy a hermit from a distant corner of the universe found, took as a student, and then introduced to the animalistic Hakaishin and his angel. When you're very young and seemingly alone, with that same elephant and that distant angel as your companions, you randomly begin to adopt other people's habits and behavior. Can Zamasu's ears change? Are they leaves stacked on top of each other? Or are they maple leaves bunched together to mimic an ear? When Zamasu is angry, frustrated, and irritated, his ears open, mimicking an elephant's ears. And maybe he looks silly, like a frilled lizard.
--
The true form of Kaioshin (and Shijin) from their Kai World is a "living tree/bush," which is a plant-like creature. Because they have an affinity for magic and ki control, they create humanoid disguises for themselves when encountering humans. They are capable of shapeshifting, and they can also change the texture of their skin when their vast number of branches and vines are able to assemble into a single humanoid creature. Therefore, if you wanted to touch a Kaioshin, say before you learned they weren't just magical dudes, they can soften their skin to the touch, so it mostly feels like tree bark.
It's difficult to spot with the naked eye the muscle-like lines on their bodies, indicating where the vines connect to each other.
Shin would have long ago stopped having "horns" on his head, even outside of human interaction, hiding them when in humanoid form, having suffered injuries and PTSD after Badidi/Bodidi and Buu. Buu definitely tore them out or broke them off, and Shin, bloodied and in pain, tried to come up with a plan to stop the cosmic threat. Damage to tree horns doesn't lead to disorientation or death; they're just one of the many vines and branches in their bodies that gather on their heads. Rather, it leads to intense pain and sensory irritation.
In Zamasu's case, he might have used the tree horns for both defense and offense. He recalls creatures and deer with similar horn patterns. He's so angry and irritated that he wouldn't care if the Saiyans broke them. He'll create new ones, drenched in ichor and sap, to finally pierce the pathetic mortals.
