Learn Japanese with Anime - I Have To Become A Hero!

Analysis

俺は悪魔なんかじゃない

“Noun A は Noun B じゃない” means “Noun A is not Noun B” as the particle は indicates the topic and じゃない shows the statement is negative.

Noun A is 俺 meaning “I” which is only used by men and Noun B is 悪魔 meaning “a devil” so 俺は悪魔じゃない means “I am not a devil”.

なんか (particle) shows that one is looking down on the preceding word.

So if it’s 俺は悪魔じゃない he’s simply saying that he’s not a devil, but by adding なんか he’s also showing that he has negative feelings towards 悪魔.

俺はヒーローにならなきゃならない

俺は shows he’s going to talk about himself.

ヒーロー means “a hero”.

The に particle used with verbs that express change such as なる (to become), 変わる (to change) and so on, indicates a target of change.

A stem of the verb nai-form followed by なきゃならない means “have to do something”.

なら is the stem of ならない which is the nai-form of なる meaning “to become“, so ならなきゃならない means “have to become”.

なきゃならない is a broken version of なければならない which directly means “If one doesn’t do it, it’s no good” so it means “one has to do it”.