The thing that I hate about Claude is not his character. He has a decent personality, and I’d like to have seen it more. The problem is where he was placed. In Black Butler. As Sebastian’s rival.
Claude is a replica of Sebastian, and to make him his rival is wrong. Most fans hate him. This is fair, because a lot of things would’ve made a better rival, for example:
A close family member, like a sister or father- No doubt that fans would have loved to learn more about Sebastian who forever remains ambiguous. A family member coming to Sebastian during his contract to quarrel about a problem and when it is unresolved the family member tried to break the pact. It would’ve been interesting to see how Sebastian had dealt with that, since he can’t just straight up kill them.
An eon-long mate recently turned ex-mate- It would be fun to see Sebastian struggling to deal with a divorced spouse. Again, we actually get something from this, unlike Black Butler II, where all the introduced characters end up dying.
A higher up demon- Say, Ciel is drinking his tea and then the door is thrown off its hinges and freaking Lucifer storms in and Sebastian is like “oh hey sir what’s up”. To see Sebastian in trouble would mean we get a bit of lore of hell in Black Butler and that would be really interesting, honestly.
To be fair, anything is better than Claude. He’s not a bad character, but just in the wrong place at the wrong time doing the wrong thing.