What does "オレ" in Pokemon Opening song mean?

Question

The lyric says:

オレはこいつと　旅に出る

I wonder what オレ means. Is it a different way to write: "俺"?

Answer 1

オレ, おれ and 俺 are used by males and mean “I” or “me”. Their meanings are same but their nuances are different.

Whether オレ, おれ or 俺 is used depends on the speaker’s or the author’s preference.

The lyricist of the song could have written it in other ways like so:

オレはコイツと
おれはコイツと
おれはこいつと
俺はこいつと
俺はコイツと
俺は此奴と

But he chose オレはこいつと, maybe because it fits the character's personality and the song.

A character using オレ is generally a boy, a young man or an internally young man. Sometimes オレ expresses the boy’s active personality, or sometimes オレ expresses the boy’s casualness (e.g. The boy’s attitude is always somewhat casual, almost never completely formal.)

The characteristics of characters using 俺 or おれ are diverse.

A character using 俺 is generally older or more intelligent or more something than a character using オレ but there are many exceptions. A character related to Japanese traditional culture tends to use 俺 rather than オレ.

Many authors tend to use オレ rather than おれ to write a character’s line when 俺 is not an option, because オレ is katakana so it makes distinguishing the word from other hiragana words easier. For example,

「さっきおれのこと呼んだ？」(Did you call me a while ago?)

「さっきオレのこと呼んだ？」

さっきオレのこと is a bit easier to read. But it wears the word オレ’s nuance, so if the nuance doesn’t fit the character's personality or situation, the author won’t use オレ in the character’s line.

Some authors have their special policy to use おれ, オレ or 俺. In that case, the word おれ, オレ, or 俺 may express the special nuance.

For example, a lot of male characters in a popular manga One Piece use おれ. The author of the manga, Eiichiro Oda (尾田栄一郎), answered a fan’s question why he uses おれ rather than 俺 or オレ. What he said is that hiragana おれ makes him feel a belief. The following is his exact words.

「一人称などは、他の文章とまざらないように「オレ」や「俺」で書く人が多いですね。でも僕は「おれ」という文字にこそ、信念を感じるのです。説明はむずかしいけど、僕は「おれ」と書きたいし、他の文字で書きたくないんです。心意気です。」
（『ONE PIECE 巻五十二』第503話後の質問コーナーSBSより抜粋）

Therefore, each of オレ, おれ, and 俺 has its general nuance expressing the speaker’s characteristics, but in some cases it can also have a special nuance which the author or the speaker intends, although they have the same meaning “I” or “me”.

Answer 2

It is as you think but while it may be a different way to write 俺 it is orthographically non-standard. Let's also the following facts in the ポケットモンスター case:

• In manga and anime it is pretty common to find words written in katakana and it's done to give a mere distinctive tone to the aesthetics of the work.
• Kana in its entirety is learned by youngsters first which are(supposedly) the target market of the franchise, in fact, you can see the Pokemon games' script is written in kana when Japanese language is set.

Answer 3

"オレは" = I (nominative case)
"オレ" = me (objective case)

"俺" is pronounced "オレ" in Katakana, Japanese.