にしろ〜にしろWhether… or

にせよ, and にしろ are two phrases that are often translated as 'even if (A)', or 'no matter if (A)'. This structure is a combination of に, and either of the imperative forms of する; せよ, or しろ. せよ tends to be more common in written material, while しろ is more common in speech. Despite the English translations, this particular use of the imperative form of する translates more accurately to 'so it's (A), who cares!', as the speaker is just strongly stating that the actual condition of (A) is unimportant in the overall sentence.

When repeated, にせよ～にせよ illustrates that regardless of either '(A) or (B), (C) is still true'. In many cases, (A) and (B) will only be a small sample of possibilities, with the actual meaning being 'in (A), (B), or any similar situation at all, (C) is still true'.

にせよ and にしろ may appear following verbs, い-Adjectives, な-Adjectives or nouns in any of their standard forms.

Caution

Although not grammatically incorrect, it is quite unnatural to mix the use of にしろ with にせよ. Due to this, when using this pattern, it will be important to repeat the same exact expression.

Fun-fact

にせよ～にせよ is regularly used with pairs of antonyms. In a broad sense, this just illustrates that 'for the opposites of (A), (B), and everything between, (C)'.