So from what I understand, the yuri genre is always written in kanji, like this, 百合. However, I noticed that the title of the anime has yuri written in katakana, ユリ. So if the anime is a yuri series, then why would they write it in katakana instead of kanji?
This is basically an aesthetic choice. There is no "one correct way" to write a made-up phrase like this. In this case, I can think of several possible explanations:
- Even if yuri is one of the themes of the anime, 百合 in kanji would look too direct and explicit. ユリ in katakana works more like a suggestive keyword, which was enough in this case.
- 百合熊嵐 would appear to be a 四字熟語 and thus feel too "traditional" or "serious".
- 百合熊嵐 is a little harder to parse and recognize because there is no clear word boundary. On the other hand, anyone can tell ユリ熊嵐 is an eye-catching made-up word instantly.
These may or may not be correct. BTW, ゆるゆり is a similar example. Here the title is in all-hiragana to emphasize the cuteness or easygoing-ness or the work. Someone who sees it for the first time may not recognize it's related to yuri, but that's expected.