Essence of theCastlevania Series

You gain a free age and appearance change to whatever you want.

You have incredibly strong willpower, allowing you to resist fear, corruption and mind control.

You are superhumanly strong fast and durable, easily a match for most Belmonts.

You are incredibly athletic and acrobatic. You can also double jump, somehow.

You are incredibly skilled monster slayer and vampire hunter, having near encyclopedic knowledge of many monsters and their weaknesses and well enormous skill in numerous types of weapons and martial arts.

You have the ability to perform Item Crashes and variants such as Dual Crashes.

You have access to Castlevania’s magic systems, and a high level of skill in magic and alchemy. This includes training in Light/Void and Dark/Chaos magic.

You have received extensive training as a Devil Forgemaster, allowing you to create Innocent Devils and other monsters, though this may require special materials.

You gain the Power of Dominance, allowing you to absorb the souls of monsters and supernatural entities you slay/defeat and gain their power as your own. This usually manifests as an ability characteristic to them adapted for your own use. The more souls of the same type you have, the stronger the ability will become. You can also find other ways to use the souls you absorb.

You gain the ability to use/form/absorb Glyphs, magical representations of power that can be used for variety of purposes (cast spells, materialize weapons, etc.). This has some similarities to the Power of Dominance in that Glyphs can be obtained from defeating foes, but obtaining Glyphs that way is much rarer by comparison and Glyphs can have wider variety of sources (such as shaping existing magic/power into a Glyph, much like Dracula’s power was made into the Dominus Glyphs).

You gain the Dual Set-Up System and all its cards, allowing you to perform a variety of supernatural abilities with them. With enough mastery of magic, you can also create new DSS cards to add to the system.

You gain ownership of Castlevania, with the castle recognizing you as its new master. The castle is enormous and has a wide variety of facilities (coliseums, kitchens, villas, labs, libraries, etc.). It's also possible to relocate the castle if needed, though that may be time and magic expensive. As a departure from how it normally behaves, it won't collapse if you die unless you want it to. You may also seamlessly merge with another base you may have. By default the castle also comes with a small army of supernatural minions (Persephone maids, animated armors, etc.) that serve you loyally, but this is optional. You may decline ownership of the castle if you want.

Optionally, you gain ownership of the Crimson Stone, which makes Death your loyal servant. You can also use it become a powerful vampire if you want.

Optionally, you have gained a Philosopher’s Stone which grants you eternal youth.

Optionally, you gain the Vampire Killer, a holy whip that is very powerful against evil and unholy creatures. You can use its full might without issues like it burning up your life.

Optionally, you may gain a connection with Chaos and be granted powers as a Dark Lord, boosting your evil/dark powers and abilities. This also makes monsters and the like much more likely to follow and obey you.

You may gain any Castlevania Series characters of your choice as companions. By default you will quickly grow a bond with them. You may choose what relationships you will develop with each of these companions (being lovers, friends, etc.). If relevant (self-insert into their world, world merge, etc.), you are guaranteed to meet these companions in-universe, meeting them in positive circumstances (this resurrects companions dead by that point, which may draw attention).

Optionally, you may Self-Insert into the Castlevania Series, a variant (fanfics, etc.), or any series with official crossovers with Castlevania (Bombergirls, etc.). You may choose when, where, and what world. The specifics are up you; maybe you get dropped in (default), maybe you insert yourself into or replace a certain character, maybe you get reincarnated, maybe you get merged with a local counterpart of yourself, etc.