Why is the past tense used in this verbs (which doesn't make sense to me at least)
生きていた…？違うな…死ねなかったのだよ…！
再生機能を持ったこのアーマーに押し込みおった
and the translation uses present tense
Survive? That's easy... Because I can't die!
And switched my body for this armor with the power to rejuvenate me
Does it make sense to use the past tense? or it's just how the character talks?
Finally I found an explanation that possibly answers at least your original question. This usage of "past tense" is called 発見の「た」 (ta for discovery) or ムードの「た」 (modal ta).
Most articles about this are written in Japanese, but here's an article written in English: Another Function of the Ta-form: Discovery and Recall
In a nutshell, my understanding is that た/だ, typically after ある/いる/ない, can sometimes express the nuance of "I've noticed ...", "I've just recalled ..." or "(In spite of one's prevoius knowledge/belief,) the fact is...". It actually refers to something in the present.
- へえ、君はフランス語が読めたんですね。
Wow, you can read French! (although I have thought you can't)- (after looking for a wallet for a while) あっ、財布、こんなところにあったのか！
Oh! There it is, my wallet!- そうでした、明日は休みでした。今思い出しました。
Yeah, that is right, I have the day off tomorrow. I've just recalled that.- (after trying to open a door) おっと、鍵がかかってた。
Oops, the door is locked.
As you can see, "fixing (or updating) one's previous knowledge/expectation" seems to be the key here. So saying 「お前、生きていたのか!」 is okay because he has believed the opponent in front of him is dead.
References (These are very long articles and I haven't read them all):
Related question:
After much investigation I came to the conclusion that the use of past tense in these sentences could mean:
1.-Showing confirmation: In the first sentence the character confirms to the hero that he indeed did not died in the explosion.
2.-Dialect: I've read somewhere that some people above 50 in Hokkaido talk with past tense when they should be using the present tense.
3.-Just how the language is: I've read that the concept of tenses is not the same for all the languages in the world, so maybe using the past tense in that way makes sense for the japanese and just need to get used to it.
