If Vali and Sugriva are brothers then why did they fight with each other?
Please explain briefly.
In the Ramayana, two monkey brothers are mentioned with importance. In fact, a complete chapter is devoted with the name of Kishkindha kand on them. The interesting story of these two brothers is as following.
Here is Sugreeva gives a report to Rama about his plight for fear of Vali, who made his own brother an enemy and abducted Sugreeva's wife. Rama asks Sugreeva to inform him about the real cause of enmity, so that he can decide correctly. Sugreeva narrates his woeful condition.
From Valmiki Ramayan
Sugreeva reports the incident that sparked off the indignation and ire of Vali towards Sugreeva. Sugreeva describes to Rama about the strength and heartless nature of Vali, with a kind of indirect portrayal of his enemy's capabilities.
"Oh, great enemy destroyer Rama, my elder brother Vali is a very dear one to our father, and even for me too he was so, earlier. After the demise of our father all the ministers have glorified him immensely and made him the king of all the monkeys as he is the elder. While he was ruling the great kingdom of my father and forefathers, I have always bowed down to him like a servant and stood by him. >There was a fierce demon named Maayaavi, the elder brother of Dundubhi and the son of one demon named Maya. There was a great enmity between this Maayaavi and Vali owing to some female. He that Maayaavi arrived at the doors of Kishkindha in a night when the people are sleeping, and blared very much inviting Vali for a fight. Then my brother who was also sleeping well, on hearing that bellowing in a clamouring voice, did not tolerate and came out speedily.
Though the females and myself bowed reverently to prevent Vali, he came out of palace in all his anger to kill that great demon. But Vali spurned all of us away and forged ahead, and then I also have started to go along with Vali in all my predisposition. A great fear was induced in that demon on seeing my brother and me too coming from a distance, and then he quickly ran away. While he is running away in fear we quickly followed him on a path that is barely lit by moonlight of the moon who is just coming up.
That demon speedily entered an un-enterable cavity under the ground, covered with grass, and we too having reached there speedily stood at the aperture of that cavity for a while. Then Vali has gone into the enfoldment of fury on observing the entry of that demon into the hole, whereby his senses felt outraged, and he said this sentence to me.
Then Vali said to me, "Now you stay here on the alert, Sugreeva, at the entrance of this hole till I return on destroying the enemy in a fight on my entering this hole..."
On hearing those words I requested him to allow me too to come in to the hole, but he being the great tormentor of his enemies disallowed it, and he made me to swear on his feet and entered that hole. Well over a year is over after his entering into that cleavage, and to me too who stayed at the entrance of the cleavage that much time had passed away. I thought I lost him for my brother is unseen, and in all fondness towards him my mind started to doubt about some harm might have befallen on him.
After a long time blood with foam gushed out that hole, and on seeing it I was deeply saddened. Sounds of screaming demon came to my ear, but the screeches of my brother who is involved in fight are unheard, in the least.
Oh, friend, Rama... I have surmised and concluded in mind by the indications that my brother is finished, and covered the cavity's opening with a mountain similar boulder, and performed water oblations to my deceased brother with saddening pain, and then returned to Kishkindha. But the ministers have persuaded and heard from me the actual happening though I was concealing it.
Then duly summoned by all of those ministers I was crowned, and while I was ruling the kingdom judiciously, oh, Raghava, that semi-human Vali returned on killing that demoniac enemy. But on seeing me crowned his eyes were reddened in anger, and he arrested all my ministers as he spoke rudely.
And oh, Raghava, though I was capable enough to counter him, my reason was controlled by my esteem to brotherhood, and I was indisposed to commit that sin of defying brotherhood. He that brother of mine entered the capital thus on destroying the enemy, and I hailed him as usual while respecting that audacious soul, but his inner self is unsatisfied and I remained unblest.
Oh, lord Rama, though I bowed with the crown touching his feet, he that rancorous Vali showed no quarter towards me." So said Sugreeva to Rama.
Sugreeva informs Rama that Vali could not be appeased in spite of repeated requests as he is resolved to accept Sugreeva as an enemy. Vali banishes Sugreeva from the kingdom with the same thinking.
"Then desiring both of our well-being I have begged of my brother who is enveloped in anger and behaving capriciously. Oh, orphan's, delight Rama, I addressed him like this, Luckily you have eliminated the enemy and returned safely, and to an orphaned one like me you alone are the protector.
Let this regal umbrella unfolded like a full moon, with its many of its spikes, and with accompanying fur-fans may please be accepted while I hold it for you. Saddened I was after staying at the entrance of the cave for one year, oh, king, and on seeing the blood that started to flow from out the cave in the entrance my heart is engulfed in sadness and my senses perturbed very much, and then covering that cave's entrance with a hilltop, and departing from that country, I re-entered Kishkindha. On seeing me returning with grief, the citizens and ministers alike crowned me, but that is not at my desire, therefore it is apt of you pardon me.
"As an estimable one you alone are the king, and I will be as I was, and establishing me in kingship is owing to your unavailability, but the capital with citizens and ministers is kept up without thorniness. Oh, gentle one, I am now returning this custodial kingdom to you, oh, enemy eliminator, you need not be hostile towards me. I beg you with my bowed head and with my prayerful palm-fold, the ministers and the city dwellers have collectively and forcibly nominated me to the kingship, only to keep the kingless kingdom under control.
"While I was speaking that politely he threatened me and indeed used many expletives starting from 'fie, fie, upon you.' and the like. And summoning people and venerable ministers he hurled very abusive words at me among friends
"You all are aware that earlier the gigantic and rancorous demon Maayaavi invited me desiring a duel in that night. On hearing his call for a duel I went out of the royal palace, and this very hazardous brother of mine quickly followed me. And that formidable demon Maayaavi ran away as he was fraught with fear on seeing me with a second one at my side, and he speedily entered a great cavity of earth on seeing us two nearly reaching him. On knowing the demon's entry into that great precarious cavity, I said to this one, this cruel looking brother of mine.
"My power will not let me return from here to the capital without killing that demon, hence you wait at this cavity's entrance, till I kill that demon and come out of the cavity. Believing that he stayed at the entrance of the cavity I entered that impenetrable cavity, and then in searching for that demon there one year elapsed. I have seen that terrified enemy of mine effortlessly, and I killed him immediately along with all of his relatives.
"That cavity has become impassable, since it is fully filled with the gushes of blood emanaing from the mouth of that demon who fell yelling onto ground. On my killing that invading enemy easily, I could not see any exit from that cavity as its mouth was closed. Wherefore I did not get a reply though I repeatedly shouted, 'Sugreeva, oh, Sugreeva.' thereby I was very saddened. With my foot I pounded and smashed that lidded hilltop, and from there I exited that way and arrived here. As such this cruel fantasist of kingdom trammelled me in there forgetting the clannishness." So said Vali to all the courtiers.
"On saying thus that monkey ruthlessly banished me, then and there in the court itself, who am with a single clothing on my body. Thus he threw me away and even stole my wife, oh, Rama, and owing to his fear alone I roamed all over the earth with its forests and oceans. I who am saddened by stealing my wife have entered this safest mountain Rishyamuka, which is impenetrable for Vali by another reason.
"All this notable account of enmity is reported to you, oh, Raghava, and you may examine the dire straits befallen on me at no fault of mine. Oh, Rama, the fear-remover of all the worlds, it is apt of you to bestow me invulnerability from the fear of Vali, and oh, valiant one, as well as to rein him in." Sugreeva requested Rama thus.