💡 Detailed Explanation
'～といえども' (to iedomo) is a formal grammar point meaning 'even' or 'even though'. It is used to state that even in the case of a highly qualified or extreme category (X), something unexpected (Y) can still happen as an exception. Here, even a battle-hardened professional fighter might lose composure. Other choices: '～とあって' means 'because of the special situation'; '～とあれば' means 'if it is a special condition'; '～なりとも' means 'at least...'.