In Western culture, it is rare calling a person only by appellation without a name; maybe, "Your majesty" or "Your highness" would be in those rare cases. But in Asian culture, calling an elder's (or superior's) name could be considered rude. So, calling a person only by appellation (or title) is quite usual. Aniki(兄貴) is a Japanese appellation calling one's elder brother. Sometimes, the appellation becomes a proper noun. For anime lovers, Aniki means a person whose name is "Ichiro Mizuki (水木 一郎)" To my grief, he passed away yesterday (12/6/2022).
Aniki is a famous anime song singer. I have a time in my 20s, watched Super Robot Spirits 2000 Live (with DVD) almost every night in my room. I believe he motivated many Otakus: not to hide in the comfort den, get out confidently, and change the world.
Probably, his most famous number was "Mazinger Z," but my favorite is Captain Harlock's opening. Thank you, Aniki. Thank you for protecting us, as it said. Rest in peace.