Essence of theIsekai Customer

This Essence tastes like a delicious tasting 'free sample' of any sort you may have previously enjoyed while shopping, defaulting to coffee or tea in absence of a better option.

• You gain the ability to use doorways as portals to other worlds, and more specifically, shops of various nature, most commonly associated with the type of doorway you crossed through.

• You gain a perfect translation and linguistic ability, able to speak and understand different languages like a native, and to read or write in those languages without any issue, for as long as you need to be able to do that.

• You gain an ability to pull a wallet out of your pocket that can exchange any currency you may place in it to the local variant, including your normal currency back home in your own world, depending on the country you are in.

• You can enter various different stores, by crossing the threshold into one in your own world, you will be taken to the best option across the multiverse that offers books on what you might need or be interested in.

• You could find a small clinic's doorway taking you to a fantasy world healer with magical abilities to fix injuries in seconds that would be incurable in your own world, including restoring lost limbs, or treating terminal diseases.

• You will still need to be able to pay for services or goods acquired, and may need to barter in some worlds where even converted currency means very little.

• You may also gain advantages through winning games and challenges in different worlds, from a carefully laid out game of chess or Go, to playing video games in a strange Modern Day Cultivation World.

• These tend to still carry some link to the game played and the world they involve. Cultivation world Chess game might draw a bounty of Chi to both you and your opponent, rewarding the winner of the game more grandly, but potentially benefiting both parties. This could make you a very interesting young man to play against for even old monsters of the cultivation world, if only for the sake of novelty value, and intrigue some for the possibilities of dual cultivation with you being a likewise bountiful experience. (Optionally, this can also be treated as a game, in which case, it might.)

• You gain only a brief visit to these worlds to acquire the goods or services you require, and may not freely wander about them, but a suitable business like a tea-house or a gaming parlor might still provide social scenes to enjoy. You will still find yourself drawn back to your own world after a time, but you may slowly develop some 'free time' to wander outside the stores in those worlds, but it is a temporary leash that will drag you back to your world soon after. This may be extended in time through practice and use, but ultimately your status as Isekai Customer is that of a visitor in other worlds, not a resident.

• You gain a fiat-backing to your purchases or acquisitions to make them work regardless of the conditions of their origin world as long as you brought them back intentionally. Otherworld parasites or virus trying to hop onto you to follow you across a dimensional gap gets fried without causing you any alarms or issue. You may eventually take a 'tourist' back with you for a short time, but they follow the same 'short visit, on a leash' sort of arrangement as you would, tethered to you rather than a store, and you may need some time to actually pull this off for even a minute to begin with.

• You may gain permanent superpowers, various immunities, protections, and other boons while traveling to various shops, but you will need to seek them out for yourself.

• (Optionally) You gain access to a 'Isekai Customers BBS' through which various world-traveling customers may compare experiences, recommend specific stores to visit in other worlds, share tips and recommendations, and provide one another with some amount of support. This may also provide short-term loans, but in such a case, the debt will be fiat-backed and will be paid, even if it means losing something of sufficient value to convert to universal credits that can be converted to suitable currency to pay off the other party afterwards.