Dragon Quest Walk aka Dragon Warrior will challenge the throne since its older than Pokémon. It’s being made by Square-Enix and it’s one of the longest-running JRPG series of all time. Since it’s a story driven game, the quests might lead to an end goal. There’s also the possibility that defeating them all are not required.
Players can play by themselves or in a party of four if the screenshot is any indication. Plus, its animation is far slicker than other products.