Koume and Kotake, collectivelly referred to as Twinrova, are 400 year-old witches who serve as major recurring villains in The Legend of Zelda video game franchise. The Twinrova are the surrogate mothers of Ganondorf. Kotake is a master of ice, while Koume is a master of fire. Their fused form is a master of both.
This biography of Twinrova is organized into the latest "official Zelda timeline", this may change completely in the future as the timeline given is merely meant as an example, and their have been official timelines before it.
The Unified Timeline refers to events before the split in Ocarina of Time and thus occurs in every timeline, the split happens in the final battle with Ganon.
Ocarina of Time
They first appear in the Nintendo 64 game, Ocarina of Time, as the boss of the Spirit Temple. They discover Nabooru, a Gerudo warrior, trying to overthrow Ganondorf and brainwash her; turning her into a Iron Knuckle. When Link invades the Spirit Temple as an adult, the Twinrova sisters order Nabooru to kill him but he defeats her and frees her from their grasp. They then make Nabooru disappear once, planning to brainwash her again after dealing with Link.
After wandering onto their sacrificial altar, Link is forced to fight them with his mirror shield. Koume launches beams of fire, which have to be reflected at Kotake, While Kotake shoots beams of ice that must be reflected at Koume. After damaging them enough, they transform into a giant, younger-looking witch called Twinrova. (They call it Kotake and Koume's double dynamite attack.) To defeat the Witch, Link must absorb three beams of fire or ice into his sheild, and reflect the attack.
Decline TimelineThis is the timeline where Ganondorf killed Link in his final battle with him, leading to the Imprisoning War described in A Link to the Past's backstory.
Oracle of Ages/Seasons
Twinrova appears in Oracle of Ages and Oracle of Seasons as the central antagonists, seeking to revive Ganon. When Link defeats Onox and Veran, it is revealed that the villains' real goal was to lit two of the three Evil flames needed to revive Ganon. Meanwhile, the sisters kidnapped Zelda in order to steal hope from the people and, in turn, light the Flame of Despair. Since the Evil King needed a vessel, they were also planning to sacrifice Zelda.
Fortunately, Link confronts the witches on time and manages to defeat them. Because of this, they chose to sacrifice their lives, but since they were not the required sacrifice, they only manage to resurrect a mindless, berserker Ganon.
The Twinrova sisters are pretty dangerous here. Koume attacks with fireballs and Kotake with ice balls, which Link must strike to send them back at the other sister. When they fuse, Twinrova can either freeze the ground to slow Link down or create lava pits all over the room. She attacks with fire and ice projectiles that divide into smaller ones. Her weakness in this stage are mystery seeds, but Link must strike her a couple of times with his sword and force her to acquire a neutral, stunned form. Then, Mystery Seeds can be fired at her with either the Seed Shooter or the Hyper Slingshot, which will damage her.
Hyrule: Total War
In this game she is one person instead of two, appearing in her fusion form. Twinrova is a servant of Ganondorf again in this game, she is a leader unit of the Gerudo and uses two swords in battle, one of ice and one of fire.