Hatred

"'The white hot rage a being can feel towards another, the burning desire to see them fall in the most violent way possible, the ability to abandon all your morals and principles to hate your foe with all your being. that is the true source of Hatred and it seems that the so called 'Princess of Friendship' is the first to ever summon it.'-Dante describing what creates Hatred and the irony that it's Twilight who summons it."

History
the power of hatred belonged to the sorcerer Acronas. this power was lost to time, though because of it's fiery and angry nature, it couldn't be inherited by anyone. after so long, Twilight of all beings summoned the power of Hatred. she was able to fight and nearly kill Dante at full power, but she stopped, which allowed Dante to take the power and adds it to his arsenal. Sunset also possessed Hatred when she summoned the power of Creation from the other heroes/villain's residual magic. later on, Dante summons the residual power of Creation and re-attains the power of Hatred.

Purpose
the role of Hatred in existence is to spark the will of life in mortals and give then drive to succeed in whatever they've set out to do. it also regulates the bad emotions mortals feel to know the wrongs they've done.

Users
Twilight: she attains it after Dante "kills" Celestia and burns down Canterlot, when she finally accepts her rage at him and abandons her heroic ideals. after she achieves the power of Hatred, she is able to overwhelm Dante, who has three ancient powers and his true magic. she is able to overcome its rage inducing effects, which allows Dante to take the power along with Harmony.

Dante: after he was nearly defeated by Twilight, he stole the power and was able to use it's immense power. it is believed that he had it already after he escaped Tartarus, but after he learned patience in the past, he lost it.

Sunset: after the others gave her the power of Creation, she gained the power of Hatred as one of her components.