Post siblings including twins who are also enemies, adversaries, or rivals

Illumi & Killua Zoldyck have a love-hate relationship. Actually, Killua is pants-shittingly terrified of Illumi, who is not unlike a walking breathing creepypasta.

Illumi is a control freak. while the only soft spot he has is for the well-being of his own family, he has no problem with manipulating or beating his brothers & even tried to kill his youngest sibling.

He also constantly threatens to hurt Killua's friends after years of telling Killua that he isn't allowed to have any friends. In the end, he decided to let his youngest sibling live only because he found a way to use said sibling for personal gain. He also seems to desire molding Killua into a mindless puppet who obeys his orders.

Killua's hatred of Illumi grows; forced to protect the youngest sibling from being manipulated as he had been, he has to leave his best friend & return to the home he was so eager to get away from. (Which is dumb...He should have just taken Alluka with him & Gon).

You'd get the impression that Illumi hates Killua, but he is very protective of him. One very strange thing about Illumi is that he's both willing to sacrifce his own life for Killua's safety & threatens to kill Hisoka if he touches Killua. He told Hisoka that he thinks he's Killua's most precious person (which Hisoka said he thought was kind of fucked up). He also said he doesn't mind if Killua kills him, because Illumi will suffer& think of Illumi at all times....So...yeah...Might love his brother a little TOO much.

Sha Jien & Sha Gojyo from Gensoumaden Saiyuki.

Gojyou works for Genjou Sanzo, Jien, bka Dokugakuji, works for their rival; Kougaiji.

Their mother used to beat Gojyo, whom was a unwanted stepson of another woman. Their father left them. One day, Jien had to kill his mother to save Gojyo. He then abandoned Gojyo & became smitten with prince who looked somewhat like his brother.

The youkai prince needed the scripture of a Sanzo monk to revive his own mother, whom was turned to stonk.

A different Sanzo is also on a mission to retrieve said scripture & kill any youkai that get in his way. This monk, Gojyo, & & two others are bound by fate to meet every time they reincarnate.

Jien & Gojyo are sometimes in a situation where they have to fight eachother by obligation. Their strained relationship is a blend of pity, bad nostalgia, resent, respect, conflicting business, & some amount of brotherly effection. They try to k.o. eachother instead of aiming to kill.

Yoh and Zeke (Shaman King)

Inuyasha and Sesshomaru (^3^)

Jin and Ragna are rivals.... well more like sworn enemies... One brings order and the other brings calamity to their world

Itachi & Sasuke (Naruto Shippuden)

Even though it was Itachi's plot........these siblings lived as enemies...........he he he eh

Kokoa and Moka are rivals in Rosario Vampire while they are enemies with their other two step-sisters Kahlua and Akua .