use of たる in 礎たる資質

Question

This is a sentence from a character bio, but for whatever reason―maybe the author's quirky―they've written it in a really verbose way in what seems to be classical Japanese. I get the general gist of most of it but this one phrase is getting me kind stuck.

[彼【かれ】]に次代【じだい】の礎【いしずえ】たる資質【ししつ】を見出【みいだ】し

[She] finds in [him] an attribute that is the next era's foundation? A disposition of those who will be founders of the next era? I feel like I've gotten the general idea (I think?) but I just don't know what would be the right way to put it into words. This is the first time I've come across たる and it's... pretty confusing.

If it helps, I'm pretty sure the sentence is referring to a scene when the character who's bio is in question thought "he could become a good leader, because being able to change peoples hearts is like a requirement (the word used was 必要条件【ひつようじょうけん】 which I feel ties into the use of たる since たる is apparently used to refer to requirements?) of leaders."

Answer 1

たる was used by to express the likelihood of becoming something or someone: 〇〇になることができる。

彼{かれ}に次代{じだい}の礎{いしずえ}たる資質{ししつ}を見出{みいだ}し。

Means the character in question has the potential to become a pillar for the next generation.

The following are simplified versions meaning roughly the same:

• 彼ならば次{つぎ}の時代{じだい}の基盤{きばん}を築{きず}くことができる才能{さいのう}があると思った。

• 彼だったら将来{しょうらい}安定{あんてい}した「社会{しゃかい}、政府{せいふ}、家族{かぞく}など」を作{つく}ることができると思った。

• 彼だったら次{つぎ}の世代{せだい}を任{まか}せられる。