Hello Author-san. I'm just read your fanfic (Guardian of Yui) and I have a criticism and suggestions. It's a good plot but you made your Oc too powerful and doesn't have any weakness. Don't worry, my diabolik lovers fanfiction also have God Mode like you but in my character, she has a weaknesses and I tried to make some characters not too OOC.
In my fanfiction, the vampires also doesn't fall in love so easily. There's a process that they will fall in love.
My suggestion:
-Try to make the characters not too Out of Character or OOC.
- Give some kind of weakness in your OC
- Don't make the vampires fall in love so easily. They are from abused family so they are not familiar with love.
I don't know if you read my message. This is not a hate comment. This is just critic and suggestion to make a better fanfiction so the readers could be comfortable in reading.