A formal or literary first-person plural pronoun meaning 'we' or 'us'.
我らはこの町を守ると誓った。
We vowed to protect this town.
戦いの前に、我らは互いに剣を交えた。
Before the battle, we exchanged swords with one another.
A poetic/literary use as a first-person singular pronoun ('I'); uncommon in modern speech.
我ら一人、月を仰ぐのみ。
I alone gaze up at the moon.
A colloquial use addressing a group of people ('you' plural), used when speaking to equals or inferiors; dialectal or informal.
我ら、さっさと行け！
You lot, move quickly!