Tribe of Ancients

The Tribe of Ancients were an advanced civilization appearing in Paper Mario: The Thousand-Year Door that was led by four sages, including Merlimbis, a female sage that created the Purity Heart, Merloo, a male sage that wrote the Light Prognosticus to counteract the Dark Prognosticus, Merlight, another male sage that designed Flipside, and Merlumina, whose spirit guarded the Pure Heart in Yold Desert for 1,500 years.

History
The ancients studied and believed strongly in the power of love (and therefore had rather wild romance relationships). They traveled to many worlds to share this belief and entrust people with Pure Hearts, the eight parts of the Purity Heart. The Pure Hearts were drawn by their own power toward those strong with love. The Ancients used this trait to find suitable guardians in each world. Many of the Ancients who found guardians fell in love with those they met. They ended up living their days happily in the world they'd visited out of duty. This is how the legend of the Hero was passed down from generation to generation.

The Ancients were wise, but they lacked physical power. They needed strength. For this, they created the Pixls for any manual labor they could not do themselves. With the help of the Pixls, the Ancients made amazing worlds.

The Ancients then created Flipside. However, Flipside was losing stability. When they came to the realization that for all light there must be dark, they created Flopside with help from the otherwise isolated Tribe of Darkness, who were once members of the Ancients. Flopside's darkness is the reason for Flipside's stability and longevity.

Their power and influence declined, however, after the Pixl Uprising.

Merlimbis
Merlimbis, who is described by Tippi as "gentle and loving", was one of the four sages among the Tribe of Ancients. She is thought to have created the Pure Hearts, and therefore possibly the Purity Heart as well. She is never directly met, only viewed in a stained glass window in Mirror Hall.

The strangely-drawn depiction of her seen in this window seems to suggest that, during her life, Merlimbis looked identical to Merluvlee the fortune teller. Indeed, both Tippi and Tiptron state that Merluvlee is a direct descendant of Merlimbis, as is the similar-looking Merlee.

Merlight
Merlight is revealed by Tippi to have been quite knowledgeable in the nature of worlds, and used this knowledge in the design of Flipside.

He is distantly related to Merlon, who looks identical to him and apparently possesses a large amount of the books Merlight left behind. Interestingly, however, the angular positioning of his hood in the stained glass window of Mirror Hall he is seen in actually makes him appear somewhat similar to Merlon's appearance in Paper Mario: The Thousand-Year Door, though this may be a coincidence.

Merloo
According to Tippi, Merloo was very wise in his time and is even thought to be the author of the Light Prognosticus. He has the appearance of a mustache-less, green-robed character slightly resembling Merlon.

Interestingly, unlike all other sages among the Ancients, Merloo possesses no current inhabitant of Flipside or Flopside who bears any direct resemblance to him, although some other "Shaman"-like characters of past Paper Mario games do slightly resemble Merloo.

It is interesting to note that Merloo is said to be a powerful, dimension-controlling magician, which relates him to the villain Dimentio. Another character known to control the dimensions is Bestovius.

Merlumina
Merlumina was a member of the Tribe of Ancients. 1,500 years before the setting of Super Paper Mario, she was told to protect the Pure Heart in Yold Ruins and await the hero of legend. 1,500 years later, her ghost still waited (albeit slightly impatiently) for the hero to arrive.