Using は or が instead of を cases


In a visual novel I ran into this sentence

嘉音くんの死亡は赤で宣言済みならば、生きているわけがない。よって、襲われた彼らが、嘉音くんと誤認するような何者かの変装の可能性がある！」

Which according to an official translation it means

"If Kanon's death was proclaimed with the red there's no way he was alive.
Therefore there is a chance that the one who attacked the group was in a
disguise to make the group mistake them for Kanon"

Is the が in 襲われた彼らが used as replacement for を

If so then why

I saw cases like 君は私が守る (Ill protect you) where the は seems to act as a
replacement to を.

Based on what and why do you use は or が instead of を. Is this mainly used when
referring to organic things.

However I also saw cases like this

瞬発力が要求される無酸素運動に関しては定評があり (There is a established opinion in aerobic exercises
where instantaneous force is required) where the が is used instead of を. (and
in this case が isn't used for an organic thing)

Can someone help me ?




Because the choice of particles depends on the choice of predicate and here
the predicate is altered through the translation. In Japanese, the subject
(襲った何者か) is omitted, and 襲われた彼らが嘉音くんと誤認するような何者かの変装（である） is the predicate
(here, である is altered with の in order to come before another nominal predicate
可能性がある. It would be easier for learners written ～の変装である可能性がある. They say the
same thing.). For easier understanding, break down the complex predicate. The
core of the predicate is 変装である=in disguise. 襲われた彼らが嘉音くんと誤認するような is a modifier
for 変装: in disguise because of which the attacked group would have mistake
(him) for Kanon (I'm not sure of my English whether I should say "because of
which", "by which", "for which", "due to which", or something). The
translation use the causative verb which the Japanese one doesn't use. If you
turn the translated sentence back into Japanese word by word,
襲われた彼らに（襲った彼を）を嘉音くんと誤認させる変装の可能性がある.




Because the choice of particles depends on the choice of predicate and here
the predicate is altered through the translation. In Japanese, the subject
(襲った何者か) is omitted, and 襲われた彼らが嘉音くんと誤認するような何者かの変装（である） is the predicate
(here, である is altered with の in order to come before another nominal predicate
可能性がある. It would be easier for learners written ～の変装である可能性がある. They say the
same thing.). For easier understanding, break down the complex predicate. The
core of the predicate is 変装である=in disguise. 襲われた彼らが嘉音くんと誤認するような is a modifier
for 変装: in disguise because of which the attacked group would have mistake
(him) for Kanon (I'm not sure of my English whether I should say "because of
which", "by which", "for which", "due to which", or something). The
translation use the causative verb which the Japanese one doesn't use. If you
turn the translated sentence back into Japanese word by word,
襲われた彼らに（襲った彼を）を嘉音くんと誤認させる変装の可能性がある.

