I have read this yaoi manga for a while, it was so good that I want to download it or at least re-read it. I cannot remember much about the main story, but the EXTRA left me a strong impression, it's an INCEST story.

2 brothers here are half-brothers, the older is Japanese, the younger is a half (however stronger build and damn tall, muscular). The older brother is staying overseas with his Mother (ex-wife of the Seme in Main Story) who has remarried with a Rich Foreign Man, the younger brother is the child of her second marriage.

The older bro is a child of the Seme in the main story with his ex-wife, he has tried to kidnap the uke of his Father once, yet failed because he was supervised by his younger bro who also followed him back to Japan. That event occured in the main story which is about the Father and his uke (much younger than him i guess).

The EXTRA is called "Love you since the day you were born" or something sounds like that, it's about a party inside their mansion (as mentioned, the step-father is Rich). A friend of the older bro (called Carlos or so) kisses him at the balcony and the younger bro saw that, then he comes up and hit that guy unconscious. Those brothers end up having "made-up" sex on the sofa right in front of that poor guy. After that the friend and the younger bro have a talk in the garden (not so sure about this detail).

There is also a flashback when they were young, the older bro sat on a tree, his younger bro came and told him to go down (the younger were so cute back there) but when the younger bro was in junior high (already look manly and handsome), the older seduced him to have sex and that is the cause of the conflict inside the Older bro's mind (he does not believe that the younger really love him and also feels guilty about seducing his younger bro).

That's all I remember, please anyone who have read it, I need the title, I'm dying to read it again. Thank you in advance!

It should be Suutsu wo Kita Akuma or one of the other volumes of the series ^^

Yup, that's IT! And I have been searching all this time!! To think that it had become series!! Fabulous!!
Thank you very much, savior!