pokemon

I think something like BotW crossed with Dark Souls.

Skip out on having a trainer. You play as a ditto, battling different pokémon which have their own movesets in battle, and traverse the environment using their techniques.

Eventually word gets out about the ditto which can freely transform and trainers begin trying to hunt you down.

Battle consists of managing your stamina. Stamina drain depends on the pokémon and the type of move.

Heavy pokémon have a large stamina drain on dodge. Nimble pokémon are great for preemptive strikes, but lack the attack power of the bigger guys.

Saving your stamina for breaking the enemy's weakness means an opportunity to transform into your charizard form and let loose a barrage of attacks, then swapping back before the enemy recovers.

Obviously elemental powers are in play, fire can be used to set grass on fire (like farcry 2), electricity can be used to shock enemies in water (like BioShock).

Defeating trainers means you can take their items, and transform into them. You need to be careful about navigating cities, as your ditto-face will alert people to your presence.

The objective of the game is to reunite with your ditto clan on the other side of the map, because you're a horny ditto, and you want to have fuck with another ditto and have a hundred babies, so you can have a hundred friends, and nobody can say no to being your friend.