Colloquial suffix borrowed from English '-s', used to make Japanese nouns sound plural or more casual. Often used in playful or trendy speech.
from English
Those idols are cool, aren't they?
possessive suffix; -'s
Colloquial suffix borrowed from English possessive '-s', used to indicate possession in a casual or trendy way. Often attached to names or nouns.
This is Taro's book.
I went to see a movie with the gang of friends.
I'm hanging out with my friends today.
I like that cafe's cake.
This is Ken's bag.
ら is a more blunt, sometimes rough pluralizing suffix (彼ら), whereas ズ carries a trendy, casual '-s' feel borrowed from English.
Katakana spelling is the most common written form for this colloquial suffix.
Hiragana spelling is also used, especially in casual writing.
Borrowed from English plural '-s' and possessive '-s', used as a colloquial suffix in Japanese.