これも後で言うつもりだったんだけどカタハネのキャラに端役というのは存在しないのよね。

。

I was planning to mention this later too, but there are no minor roles among the Katahane characters.

Literal

This [also-も] later say plan [copula-だった] [explain-んだけど], Katahane [gen-の] characters [to-に] bit-part [called-というの] [topic-は] exist-not [feminine-のよね].

~つもりだった 'was planning to' uses the past of つもり to mark an intention that was held but perhaps overtaken by events. カタハネ is a visual novel title used as a proper noun. 端役 'bit part / minor role' is standard theater/entertainment vocabulary. The sentence-final のよね stacks the feminine-explanatory の + assertive よ + confirmation-seeking ね — a distinctly feminine speech-end.