Your an ancient creature that you pick the design of that’s been sealed in a temple who’s been there 1000s of years some adventures accidentally free you (you pick how) your in a fantasy world with dragons monsters and magic

Your are a monster or a creature of some kind like dragons or something who’s been captured put into an arena and forced to fight other creatures and other things for human amusement

There’s a Mech war mech pilots vs mercenary’s you are a creature from the cosmos choose your own design and appear during the battle you can choose to help either side

Your a mech with a pilot your sentient but your pilot doesn’t know that but still scolds you for making mistakes choose your design and mission before starting

You are a pilot or mech you choose, you have 2 mechs under your control (you choose design and what they can do) to fight aliens other robots and monsters on an alien world you’ve been deployed at

Your a giant robot being built for a tournament choose your looks and prepare for battle

There’s a part of the ocean that people want to explore sending divers as much as possible to explore it. You are a leviathan a giant sea monster trying to get rid of them either befriend them or hunt them (you can’t talk physically but maybe psychically?) choose how your own monster looks