Sailor Starlights

"Penetrating the darkness of night, streaking through the atmosphere, resounding truth, we are three shooting stars!" — Sailor Starlight's introduction

The Sailor Starlights are a group of Sailor Senshi who came to Earth in search of their princess after their home planet was destroyed by Sailor Galaxia.

The Starlights consist of:

Their search for their princess brings them into conflict with the senshi of Earth, specifically with the Outer Senshi, who want the invaders to leave their planet and leave Usagi alone. The reason they are so interested in her, specifically Star Fighter, is because Usagi carries the scent of Princess Kakyuu due to an incense burner that Chibi Chibi possesses.

Manga

The Sailor Starlights were searching for Princess Kakyuu, the princess of Kinmoku, traveling the galaxy and eventually arriving to Earth to find her, forming a band called "Three Lights" in their civilian forms. They disguised themselves as men by crossdressing in their civilian forms so it would make more sense that their songs spoke about "finding their princess", as well as to get more publicity for their band.

First Anime Series

The Sailor Starlights are essentially the same in the anime as in the manga. One key difference however, is that they disguise themselves on Earth as biological men, and only become females when they take their Senshi forms.

Sera Myu

Just like in the manga, the Starlights cross dressed as men but were actually female.

Trivia

Naoko Takeuchi, who specifically decreed that only women could be Sailor Senshi, wasn't pleased with the fact that they could change gender in the anime.^[1]
In the manga, each of them can grow a pair of angelic wings.
Fans speculate that they have a connection with the Hindu Trimurti; the creator (Sailor Star Maker), the sustainer (Sailor Star Healer) and the destroyer (Sailor Star Fighter).