even if; even though; even granting that
Concessive expression meaning 'even if/though'. Used with verbs, adjectives, or nouns to acknowledge a condition while stating that the main point still holds.
Even if it rains, the game will probably be held.
Follows a noun to mean 'even' or 'also', often implying that something is true for that noun as well as others. Similar to も but with a slight concessive or emphatic nuance.
Used in the pattern ...にしても...にしても to list alternatives, meaning 'whether ... or ...'. Both options lead to the same conclusion.
no matter (what, where, who, etc.)
Follows an interrogative word (e.g., 何, どこ, 誰) to mean 'no matter what/where/who'. Emphasizes that the statement holds regardless of the specific answer.
No matter who you are, this job is tough.
Even if he comes, I don't think he'll come right away.
Even he would say the same thing.
This problem is difficult even for experts.
Whether you go or not, you need to contact them.
Whether it's a dog or a cat, keeping a pet comes with responsibility.
No matter what you do, planning is important.
としても means 'even assuming that' and is limited to nouns or clauses, while にしても is broader and can also follow interrogatives or list alternatives.
ても is the plain, general concessive particle for verbs and adjectives, whereas にしても is more emphatic and can attach directly to nouns.
にしろ is a slightly more formal, written-style equivalent of にしても used in the same 'whether...or...' or 'no matter' patterns.
にせよ is a stiff, literary variant of にしても, common in formal writing rather than casual speech.
にしては means 'considering that...' and points out an unexpected gap, whereas にしても means 'even if/even granting that' and concedes a point before making a contrasting statement.
Derived from the particle に combined with しても (the て-form of する plus も). The exact historical development is uncertain, but it functions as a fixed concessive expression.