They have developed teleporters on an interplanetary scale and advanced bioengineering and cybernetics which allow them to create large artificial beings and to modify themselves. High ranking officials will usually have undergone extensive modifications, often giving them giant proportions and non-standard physical features.
They came to Earth some 200 000 years ago with prospect of invasion but halted their plans upon discovering the planet atmosphere was not fully compatible with their biology. Their scouting party nevertheless stayed on Earth and established a secret base at the bottom of the Pacific ocean.
Toward the end of the 20th century, they realised that their homeworld was doomed as another planetoid was on a collision course with it. They reestablished plans of Earth conquest but were defeated.
Source: MagneRobo Gakeen TV series