Why was arimanes jealous of ormuzd in "ormuzd and arimanes"?

ormuzd had a beautiful wife.

arimanes wanted the favor of their father.

ormuzd had created so much good in the world.

arimanes was jealous of his brother's strength.
ormuzd, the king of light, and arimanes, the prince of darkness, both emanated from the eternal one, and consequently were brothers. arimanes, who was the second emanation, became jealous of ormuzd, the first born. because of this, the eternal one condemned arimanes to remain three thousand years in the realm of shadows, where no ray of light could reach.
during the time of this exile, ormuzd made the firmament , the heavenly orbs, and celestial spirits, without arimanes’s knowledge. when the period of his banishment expired, he came forth from the shadowy realms of his exile into the light; and, dazzled by its beauty, his old feeling of envy returned to such a degree that he resolved to compete with ormuzd in everything.
he found that ormuzd had created six amshaspands, - immortal holy ones, - guardians of the six planets, and attendants on himself, who presided over the seven. arimanes now created seven spirits, called archdevs, in opposition to the amshaspands; and attached them to the seven planets. his goal was to paralyze the amshaspands efforts of good and instead to substitute evil. when he found that ormuzd had created twenty-eight gentle and kindly spirits, called izeds, who govern the sun, moon, and stars; showered beneficent gifts upon the earth; worked to protect it from evil influences, and serve as messengers between men and the superior spirits, arimanes was furious.
he made twenty-eight sprits, called devs, to defeat the influence of the izeds by spreading all manner of disorder and distress. and for the leader, he created a serpent with two feet, named aschmogh. but his work was not yet completed; for ormuzd, in the plenitude of his power, had created another order of spirits , called fervers, - who were infinitely more numerous, for they were the ideas which ormuzd conceived before he began the creation of the world. hence they were the models of everything that existed; they animated all things in the universe; and were the guardians of stars, men, animals, plants, and all other created things. every mortal had one of these spirits by his side through life to protect him from evil. even ormuzd himself was supposed to have his attendant ferver.
arimanes set about making a multitude of genii, who opposed the benevolent operations of the fervers; so that everything had an attendant bad spirit as well as good one. perceiving the industry of his brother arimanes, ormuzd began creating again; he made an egg containing kind spirits. but armanes made a counterpart, containing an equal number of spirits of hatred. then, to add to his disastrous work, he broke the eggs together and good and evil became mixed in the new creation. after this, ormuzd created the earth and its inhabitants . this was done is six successive periods, then, on the seventh, there was a festival among the good spirits.
ormuzd created a guardian spirit to watch over every human being. arimanes made an evil spirit to tempt them through life. these wicked ones slipped into thoughts and said, “it is arimanes who has given the sun, the moon, and all good things.” and when they listened to his whisperings, arimanes cried out loud from his realm of shadows; “o men! worship me! ”
to harass and destroy the good animals of the earth, arimanes made wolves and tigers and serpents and venomous insects. by eating a certain kind of fruit, he transformed himself into a serpent, and went gliding about on the earth to tempt human beings. his devs entered the bodies of men, and caused diseases of the mind and body. they entered into human minds, and incited them to lies, revenge, and savagery. into every part of the world they introduced discord and death. when ormuzd tried to lead men against arimanes, they deserted him and joined the enemy. this allowed arimanes to gain the ascendency for three thousand years.
after arimanes’ rule, his power will be destroyed. ormuzd will rule again, bringing goodness to the world. there will be an end to evil and death.
adapted from indian myths by ellen russell emerson
this is the story