Daath now
Daato was used to hide from author but then people started using Daato on the mangaka's twitter so they changed the name to Daath. Read it on one of the translator's note
Daath
Not used because wanted to hide, rather didn't knew how to translate it at 1st:
Here's translator's note:
http://www.mangago.zone/read-manga/remnant_kemonohito_omegaverse/uu/remnant_kemonohito_omegaverse-chapter-6/2/
Daato is more the way you pronounce the name Daath in Japanese
I'm kinda confuse....what is his real name?..daath or daato? Or it's just the same?? But yeah...I love this story!!