Hagane no Kokoro

Take-back-show, grasp-it-is-you-see this hand-with, smile-and-tear-of-trace (obj)

取り戻してみせる combines 取り戻す ('take back') + 〜てみせる ('I will V — watch me'). The 〜てみせる ending declares resolve as performance: 'I'll prove I can do it.' のさ at the end of つかむのさ is the masculine explanatory final particle — like the よ on a sentence but more matter-of-fact.

Knowing, that feeling, that's-why worry it-is

わかってる is the casual contraction of わかっている ('I understand / I know'). 〜なんだ ending is the explanatory copula — the speaker is justifying or clarifying. Closer to English 'see, that's why I'm worried.'

Together is-yo, any-kind-of time-even

どんな時でも ('any kind of time / no matter when') is the all-times concessive — like どこでも ('anywhere') and 誰でも ('anyone'). The 〜でも after 何/誰/いつ/どこ/どんな = 'no matter what/who/when/where/kind.'

Steel-of-heart, one-person-each think feeling as-for, different-even-if

ハガネ in katakana — same as the kanji 鋼 ('steel') that gives Fullmetal Alchemist's protagonist his 'Hagane' nickname (鋼の錬金術師, 'Steel Alchemist'). ココロ in katakana stylization for emotional heart. Title-character pun built into the chorus.

Consideration as-for, certain because, any-time-even believing-can-stay

思いやり ('thinking-and-sending' = consideration / empathy) is one of the most prized Japanese virtues — anticipating others' feelings and acting accordingly. 信じていられる is the potential of 信じている ('be believing'): 'be able to remain believing.' The compound stresses sustained, ongoing belief.

We as-for lost things many but, that's-why-precisely strong-can-become

だからこそ adds 〜こそ (precisely / exactly) to だから (because) for emphatic 'precisely because of that.' The pattern frames loss not as cost but as condition — Fullmetal Alchemist's whole philosophy in one phrase.

Bond strong-and deep because

絆 (kizuna) the bond — Fullmetal Alchemist's ongoing motif of brotherhood. The two adjectives 強く + 深い chain in adverbial-adjectival form: 'strongly deep' — both qualifiers stack on the bond.

Truth as-for, knowing-sa, you (subj) side-at without-being, I alone-as-for, anything can't-do

いなきゃ is the casual contraction of いなければ ('if not being'). The full meaning is conditional: '(if it weren't that you're) beside me, I can't do anything.' お前 is rough masculine 'you' — used between brothers (Edward to Alphonse), buddies, or down-direction. The whole verse is Edward's vulnerability moment in song form.

All as-for, share-mutually-let's, joy-and sadness-even-also, wrap-give-you, always kindness-with

分かち合う ('share-mutually') uses the V-合う suffix for reciprocal action — divide and share with each other. 包んであげる ('wrap up for you') uses 〜てあげる, the polite-direction giving — speaker doing for the listener (opposite of 〜てやる).

Flowing time as-for, cruel but, overlap feelings (subj) if-certain, any-time can-keep-going

進んでゆける = 進む + 〜てゆく in potential — 'be able to go on advancing.' The literary 〜ゆく vs 〜いく gives the line a more poetic register (same shift seen in 'Yuusha' from Frieren).

Steel-of-heart, hope even lose kind-of fate even, together if, can-overcome

希望さえ失うような運命 stacks 〜さえ ('even') + 〜ような ('the kind that ~') for compound modification: 'a fate of the kind that loses even hope.' Common literary stack for emphasizing extreme cases.

Kindness (subj), decided feelings (subj), that power (obj) gives, steel-of-heart

Two が clauses chain — '優しさが' and '決めた想いが' both subject the next clause. The structure is dense: 'kindness, feelings (it) decided, give that power.' Songwriters use this for layered subjects, leaving the listener to assemble.