Family love

(Possible) step-brotherly love.

Step brothers.

A pair of twins fell in love with their adoptive father

Chapter 5 is about blood related brothers and a bit of bestiality (more like the pervert cat sucked on one of the characters' nipple, instead of the other way around). Chapter 6 is love between step brothers.

The second pairing is a "mori" older brother x younger brother. Not sure if it can be put into incest since the older brother is actually a monster who took the appearance of the real older brother (who died few years back).

Step brothers. Yakuza x host. Tatsumi's mother died on her honeymoon after she remarried. A few years later a letter came that told him that he'd inherit his step father's assets, along with a guy who claimed to be his step brothers and the head of a yakuza group.

Uncle x nephew. A young violinist fell in love with his uncle, but his uncle was getting married.

Step brothers. They were in love with each other, but scared of their unproductive love, the older brother left and married a woman. Years later, now divorced, he returned back home and met his brothers again.

No blood relation brothers. Kei has a younger brother who is beautiful and excel in everything that he does, but he knows deep inside that his brother was adopted or that he is not normal. When his brother's birth father, a very young-looking man who is supposed to be older than his father, appeared, Kei knew for sure that something was wrong.

Half-brothers. Tatsuya was searching for his younger brother when he met Haru. He thought he had found his true love, but then he found out that Haru is the younger brother he was looking for.