[i-adj 〜い → 〜かれ] + [i-adj 〜い → 〜かれ]
かれ~かれ is an old adjective ending that survives in a few fixed pairs of opposites, meaning "whether A or B". おそかれ遅かれはやかれ早かれ is "sooner or later", おおかれ多かれすくなかれ少なかれ "more or less", よかれ良かれあしかれ悪しかれ "for better or worse". New pairs can't be made, so learn these three as words.
かれ is the classical command form of an adjective: 遅かれ is 遅くあれ, "be it late". 悪しかれ comes from 悪し, the classical form of わるい悪い, which is why that pair doesn't follow the modern adjective.
遅かれ早かれ and 多かれ少なかれ are at home in ordinary conversation as well as writing. 良かれ悪しかれ sounds more formal and turns up mostly in writing and commentary; in speech, いいいみ意味でもわるい悪いいみ意味でも says much the same.
良かれ also stands alone in よかれとおもって良かれと思って, "meaning well", "with good intentions". It usually leads into something that went wrong.