If you have played and love Ken ga Kimi, this is an alternate world related to Ken ga Kimi. Similar to card collecting but you're collecting characters instead. There's an auto system and skip button but of course you need to finish perquisites before unlocking them.
Grindy and forever lacking in onigiris but the grind is worth it. If you can read Japanese, give it a try. There's an alternate TW server (if I'm not wrong and it's TW server) if you prefer reading Chinese ver Japanese.
Mentioned games