In conclusion, read the story but don't read the extra chapters. not only it ruins the story but it also leave you with a very bad taste in your mouth.
This ending(extra chapters ending) left me with a very bad taste in my mouth. To let rugal just show up and then leave out of nowhere was very unsatisfying and kind of felt insulting to the readers!
If they would end it after they finish reading the diary, that would have been a much better ending and maybe add Brett and Dio moments. but the other moments with Rugal son and Rugal was so frustrating and disgusting. I don't get why comic's and media love to save villains so much and not give them any punishment or even consequences for all the suffering/death they did to everyone. I hate this kind of bad trop.
I really like this story but this kind of ending kind of ruin it for me. A shame for this good story and characters.
Nevermore