カタカナ Analysis

Katakana （カタカナ）is a type of character in Japanese language generally used to represent foreign words and onomatopoeia. Also, katakana is a way to emphasize a word or a sentence. However, analyzing some katakana on mangas, I realized it can be used to conveyi   few more information. 

Let's see some examples:

As you can see in that example from Dragon Ball manga, the word  ぼく（僕）is written in katakana （ボク).  In my opinion, ぼく is written in katakana in order to express a fragility of the character, who is a child. Also, it is a way to convey the character's naivety.  In that case, katakana is used to express character's throughts from his manner to "speak".

Let's see another example.

In that example the name りょうこ, which is clearly a Japanese name and not a foreign name, is written in katakana. It may have been written in katakana to inform to the readers that  リョウコ is　 not a real name of the manga author. It's a pseudonym. Also it may be an attempt to turn a Japanese name in something different as a foreign name.

Some more example:

We have here two different words. One is バカボン. This word doesn't exist on a Japanese dictionary (at least I couldn't find it), but everyone in Japan knows the meaning (according to my Japanese friends). It's something like " very silly". Katakana was used, in this case, to express a "new" word, a neologism.

The other word is quite simple はりっけ, which means to crucifix. Katakana is used to emphasize this meaning.