wait what is gantz? if it's similar to Terror Infinity then try Death Notice Infinity Armament The Ultimate Evolution Arena they're all survival
Gantz is a great manga, where a group of people go on to fight aliens in the real world they were kind of randomly selected when they were on their dying moments its kind of epic, but not sure how much would i like to just read about it
there is a gantz 3d CGI ova series coming out soon sadly the anime isn't getting rebooted even though the manga is ended
Life Howling, which I like to refer to as Terror Infinity the manhwa, and Terror Infinity I consider as Gantz the novel. Try both.
So you mean, where the main cast of characters routinely rotate? Um, Kamisama no Iutoori fits the bill. It's a manga though.
I actually interviewed Hiroya Oku the creator of Gantz and he said that there are no current plans for an anime but he wants a live action movie to come out