So, forever now I've always been asking on every chance anyone i know for something similar... Basically i absolutely loved the 'Structure' of the manga of gantz. with the entity summoning (The mysterious black ball in gantz) and with the entire missions/score system/rewards/etc' and the progression/powerup/leveling or what have you through that. The closest i could think of in terms of novels would be the beginning part of 'Sovereign of Judgment'. those that read it or at least the first half or maybe even beginning 100 chapters or so would probably understand what i mean. Now, i've also heard that the 'Infinity' genre sorta can fill into the 'Like gantz' point of mine but then i heard arguments that gantz technically isn't infinity because it isn't visiting any game/movie/etc' worlds, but i did hear that there is that system/missions/rewards/progress feel of gantz to it and someone i remember even said that Gantz might have been a factor to jump start this entire Infinity genre as a whole. I would really love to hear if people that loved/enjoyed gantz and also read Sovereign of Judgement and kinda get what i'm looking for can recommend me something they believe have the same feeling or what i'm looking for. Thanks in advance!