Infinite Time Rewards

You need to complete wave 25 you should have more than 25,000+ shards by the end of that wave. After that just die and get your infinite infinity chest. That should only take you 20-40mins (depends on if you're in a group) not a hour but unless you're trying to beat your record there's no reason to go any higher than what i stated and you need to pass wave 25 for a chance at a legendary character piece, least that's what they say.

sadly there is not a 100% chance that you will get a legandary character piece in the end though. I also got the infinite chest and ended up getting the 25,000 coin reward twice. You have a pretty big chance on getting it but it's just bad luck if you don't get one out of it. You should also check your stickerbook after you finish as you are sometimes rewarded more than just one item. I got a sticker piece for the party rose but when i went back i instantly had her unlocked because i was rewarded two pieces even though it only showed me one sticker piece.