Toa Metru was the name given to the six Toa heroes who defended Metru Nui against Makuta, the Morbuzakh, and the Dark Hunters. The Toa Metru were Vakama, Onewa, Whenua, Matau, Nuju, and Nokama. It was believed that these six were the first Toa to take this name, as the previous Toa serving in Metru Nui were not native to the city.
Toa Hordika was the name given to the six Toa Metru when they had been transformed into half-hero, half-beast forms by Visorak venom. The Toa Hordika were equipped with new tools and Rhotuka launchers but constantly had to fight with their own bestial sides.
In the time before time, six Matoran were mysteriously gifted with the powers of Toa. Their destiny was to protect the city of legends, Metru Nui, from all evil. These Toa Metru had to master their elemental energies and Toa tools, uncover the mysteries that threatened their home, and learn to be heroes.
The Toa Metru fulfilled their destiny by saving the Matoran from Makuta.
The destiny of the Toa Metru was to save the Matoran of Metru Nui.
The Toa Metru were Toa for a few months.
The Toa Metru were the first Matoran from Metru Nui to become Toa.
The Toa Metru did not know how to use their elemental powers well at first, so they tended to use too much too fast and run out. They also had to be more careful about how they used them. They were in a city, not a wilderness, and creating tidal waves, blizzards, etc. would do a lot of damage to the city, so they had to be more subtle about how they used their powers.
"Metru" was the traditional name for Toa teams defending Metru Nui.
The Toa were half Toa, half Rahi.
The Toa Hordika's faces could not be infected.
The Toa Hordika could do anything with their Rhotuka that they could have done with their elemental powers as Toa Metru.
The Toa Hordika could not charge anything with their tools besides their Rhotuka.
Toa Hordika were physically stronger, but had weaker willpower and less discipline than standard Toa.
The Turaga of Mata Nui formed personal, almost paternal relationships with the Matoran they governed.
The Turaga were slow to trust the Toa Mata/Toa Nuva because they had been betrayed in the past. They were determined to place their trust wisely, which they were not quick to do.
The Turaga were not actually older than the Matoran; they were revered as elders based on experience, not age.
According to the story bible writer, after several thousand years, the Turaga's memories naturally got jumbled with prophecies to the point that they could not always keep things straight, which is why they spoke in riddles.
The Turaga's philosophy was to keep friends close and enemies closer. They preferred having Ahkmou where they could keep an eye on him.