Meg

Meg is the one, and the eldest, of the four Poe Sisters that Link will meet in the Forest Temple in Ocarina of Time, and likewise in Majora's Mask, in the Ikana Canyon region.

Ocarina of Time
Meg, the last Poe Sister to be found in the Forest Temple, uses the the temple's main room as her battleground, and appears only after Joelle, Beth, and Amy have been defeated and their respective torches lit. Her battle technique is vastly different from her sisters; she replicates herself into three other clones and begins to spin about Link. Although her technique is intimidating, her true form is easily recognizable - the real Meg will be the first to spin around once the four "Megs" have surrounded Link. Meg can be struck by Link's trusty Master Sword, slung by arrows, and interestingly can even be injured by the Hookshot. Mistaking the true Meg for an illusion will cause the fake to disappear, giving Meg a chance to inflict damage. Four strikes on the true Meg is enough to dispell her and light the final, purple torch in the center of the temple. Meg's death and the lighting of the four torches will enable Link to access the temple's basement, where the temple's boss, Phantom Ganon awaits.

Majora's Mask
Meg makes a cameo appearance at Ikana Canyon in Majora's Mask as a function of a small in-game event; Link can battle all four of the Poe Sisters to earn a Piece of Heart in the Spirit House nearby for 30 Rupees. Here, Tatl identifies Meg as the oldest of the Poe sisters.

Trivia

 * Before the battle starts, the Poe seems to be crying. This might be because her sisters were defeated, hence she reveals herself after her sisters have perished.