Tanjiro harem

So in this UA Tanjiros father is alive and is a hashira and he finds out that his family attacked and went to see what happened and who lived but sadly it was only Tanjiro so he taught him how to use sun breathing but what happens when the other hashiras found out about it and fall in love with the boy

Also Tanjiro is 17 in this and his father is 40 and he unlocked the mark but it doesn't kill unless you use it to much then it will