Essence of the Cultivator
By consuming this essence you become as ridiculously overpowered and blessed with potential and luck as the greatest of xianxia main characters. Which, if you know xianxia, is pretty damn ridiculous.
*You gain the ability to 'cultivate' your 'internal energy', allowing you access to increasing tiers of effects and powers in-theme for wuxia and/or xianxia, the exact nature and power level of these effects depending on what degree have cultivated it to. You may use an existing cultivation system from any xianxia novel or create your own.
*You may grant this ability to cultivate to others and teach them your system, but they are limited to their own willpower, comprehensive abilities, and talents when it comes to success. You may still use external means, such as alchemy or creating and sharing secret techniques, to help them.
*Cultivating your internal energy slows down your aging, eventually making you truly unaging. Likewise, you may eventually transcend mortal needs such as sustenance, normal rest, or needing to breathe. Your mind and soul will be adjusted so as to be able to endure immortality.
*Your talent for cultivation and speed and ease of learning at all things related to cultivation (including martial arts, alchemy, and creating artifacts) is beyond ludicrous. Your aptitude is raised to the maximum possible allowable in existence and perhaps slightly beyond even that. You can choose to slow this down when you need to or when you wish to avoid attracting attention.
*This includes your ability to make use of external cultivation aids, such as parts from mystical beasts and exotic plants and treasures. You may easily consume and gain maximum benefit from such things even without preparation, and gain even greater benefits from them with sufficient preparation and alchemical knowledge.
*Even if your cultivation system does not normally provide you with one you will still be gifted with perfect memory, including infinite storage and perfect indexing.
*As one specially blessed by this Essence and the heavens, you may ignore the usual limits of your cultivation system whenever you find it convenient. You may mix incompatible elements, cultivate female-only arts as a male or vice versa, ignore dietary or behavioral restrictions normally required of cultivators, etc.
*Your cultivation cannot be 'crippled'. Injuries that would normally destroy your cultivation instead merely temporarily wound it, but you can heal in time. Likewise, any cultivation techniques that carry a risk of death if performed incorrectly are entirely safe for you; you may or may not succeed at them but failure will never kill or permanently injure you, and you may try again.
*Your cultivation never dead-ends or gets trapped in a bottleneck. Regardless of what choices you make or what system you are in, there are no 'traps' that leave you stuck at a given stage of cultivation forever. All setbacks are clearable with enough hard work and your 'foundation' is always ideally solid.
*Your willpower is truly unlimited, unbreakable, and unsurpassed, and you have a perfect sense of 'self'. No amount of pain or hardship can deter you, no illusion can trap you or bind your heart or soul, and you can focus on a task for eternity if need be. Any cultivation challenges that depend on strength of will or clarity of mind are auto-win for you.
*You have the luck of a top-tier xianxia protagonist. Coincidence and fate favor you greatly, mentors and training materials seem to be available whenever most needed, discovering treasures and rarities seem to be much more common for you than for other people whenever you go exploring and adventuring, and you have plot armor sufficient to survive almost anything.
*Cultivation is not for the idle, but instead for those who struggle and overcome challenges. Regardless of how powerful you grow you may always find things that challenge you if you make a sufficient effort to seek them out, until you finally stand among the highest of beings.