also: おれ
pronoun
Dated, rough, arrogant male first-person pronoun. Used to assert dominance or in a self-important manner. Not used in modern polite conversation.
乃公が相手になってやろう。
I'll take you on.
乃公の言うことを聞け。
Listen to what I say.
Gikun reading; the kanji 乃公 is read as おれ in some contexts, but this is a non-standard reading.
The kanji 乃 (archaic possessive or emphatic particle) and 公 (lord, prince) combine to form a self-aggrandizing pronoun. The exact historical derivation is uncertain, but it reflects an old, arrogant male speech pattern.