All the way back in v1.5 we had information that a yaksha teamed with the Millelith to face off against the Abyss. But without much else to go off of and since the location of their epic battle only released about a month ago I think most people dismissed it. Now it's a month into the Chasm's release and we know a bunch more now.
And hopium abound because the new information is lining up with what I had originally proposed for the Chasm.
So the story goes that when the Cataclysm happened the turncoat Electro Yaksha returned to redeem himself to Morax. Without being ordered to do so he went to the Chasm where Rhinedottir had sent her troops and met them in battle. In response Morax personally ordered the Millelith to assist him.
After the battle many Millelith had died and the yaksha had either joined them or not but nobody ever saw him again and even Morax believed he had died. So until new information comes out I'm going to agree with the Artifacts and say he totally died and not only did he die but he vanished without a trace.
And here's maybe a replica of his yaksha mask too!
In my theory I said that I believed the Electro, Hydro and Geo Yaksha were the traitors among the Five Yaksha with Xiao surviving intact while Murata went insane out of fear and fled. Meanwhile the three damned yaksha would end up alongside some of the other fallen yaksha forced by their karmic debt to haunt an area I decided to name the Demon's Lament. And in particular I picked the Chasm to be that area.
Now we know that after becoming evil the Electro Yaksha returned to Liyue (heading east into the Chasm which means he had probably fled towards the direction of Sumeru?) in order to help fight the Abyss Order as a way to repent. But ultimately he died during the conflict or at least nobody's seen him since.
What if he was down there and he fought hard against the Abyss. As a yaksha especially one of the five we know he's powerful. Xiao is our example. And with an army of Millelith helping him not to mention that they did end up winning we can guess that the Abyss became desperate during the fight. What if instead of a natural creation of the Demon's Lament the Abyss forces ripped into the Ley Lines down in the Chasm. As its memories poured out some of them were of the other dead yaksha especially his former teammates the Geo and Hydro Yakshas that betrayed each other. (We know this can happen thanks to Ei's Character Quest.)
By this point the Abyss was already crippled so the Liyue forces did win. But with so many dead Millelith and him being likely the farthest down nobody knew what happened to him. What happened was that these ghost yaksha continued to fight each other and this racked the Electro Yaksha with guilt over his own misdeeds.
Karma was definitely a thing down there and after what he'd done he'd be feeling it all weighing on him and he probably fell. Now last time I explained it in Buddhist terms but how would that work in Genshin? Once again it'll be the Ley Lines. We saw in Ei's quest how even those minor memories were weighing on her and it caused her to think about her sister's death. So for the yaksha who betrayed the others it could have twisted and trapped him down there doomed to forever relive his mistakes. Eventually that destroys his physical body so he's "alive" but I wouldn't really call it alive. 
When we eventually find our way down to that part of the Chasm it'll be to hear his story maybe even hear the Hydro and Geo Yaksha's story too about how they turned on each other. It can't actually do anything for them but at least someone will have heard them. And yes I still believe Xiao and Murata will be there for it too. That'll give them all closure.
What do you guys think? If there really is a Demon's Lament area down there loaded with yaksha ghost enemies and a Boss fight against the 3 dead yakshas would that be cool?
Tips and Tricks from a Super Casual Genshin f2p
