 If you liked
Finder Series
|
 ...then you might like
Bi no Kyoujin
|
Intense, action-packed and hardcore yaoi manga series about Mafia/Yakuza with beautiful art. Both have non-girly ukes that become loyal to their possessive semes as time passes. There are hints of romance(slow-paced indeed). If you like Bi no Kyoujin, I think you'll also like Finder :)