conditional N1 rare writtenliterary
〜であれ〜であれ — whether ~ or ~
〜であれ〜であれ ・ であれであれ
A full written guide for 〜であれ〜であれ is on the way.
This point is mapped in the grammar tree, but its examples, formation table and usage notes haven't been written yet. The fastest way to learn it now is to meet it in real sentences inside Jengo.
See 〜であれ〜であれ in real sentences
Jengo shows 〜であれ〜であれ the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Advanced Japanese Grammar. Editorial confidence: medium.