How to Get Reiatsu Cores in Sailor Piece and Why You Need Them

Whether you’re ascending or you want a certain sword, Reiatsu Cores are a crucial item. In Sailor Piece, the true challenge is the boss fights.

Sailor Piece Reiatsu Core

In Sailor Piece, Reiatsu Cores have a few purposes, but first, you need to obtain them.

• Obtainment method last verified on the 9th of April, 2026

How to Get Reiatsu Cores

There is a singular obtainment method for Reiatsu Cores, and that is by defeating the Aizen boss. Upon defeat, Aizen has a 3% chance to drop this item, making it one of the rarest rewards from the battle.

Aizen also drops:

• Haki Color Reroll
  • 100% drop chance
• Race Reroll
  • 85% drop chance
• Trait Reroll
  • 75% drop chance
• Boss Ticket
  • 45% drop chance
• Dungeon Key
  • 30% drop chance
• Mirage Pendant
  • 20% drop chance
• Illusion Prism
  • 8% drop chance
• Reiatsu Core
  • 3% drop chance
• Manipulator (Title)
  • 2% drop chance
• Aizen Haori
  • 2% drop chance
  • Buffs:
    • DMG increases by 40%
    • DEF increases by 50%
    • DMG is reduced by 15%
• Hogyoku Fragment
  • 1.2% drop chance

This boss has 25 million HP and is located in Hueco Mundo. Aizen tends to spawn every 7 minutes and 30 seconds, so don’t worry if you miss him after arriving.

Reiatsu Core Uses

What do you need Reiatsu Cores for?

Ascension

Particularly, the 4th Ascension level. For this Ascension, you need:

• 4x Reiatsu Cores
• 1x Blood Ring
• Use any of your abilities 500 times
• Clear the Shadow Dungeon on Medium difficulty a total of 10 times
• Defeat 625 NPCs
• Deal a total of 1 billion damage
• Defeat 50 bosses

The main benefit of ascending is the buffs. These buffs stack, and after the fourth Ascension, you earn 10% more Gems, your Luck stat increases by 5%, and Cooldown times are reduced by 2%.

To ascend, you must speak with the Ascensions NPC who resides on Sailor Island. If you’re struggling to find them, just look for Killua (from Hunter x Hunter).

Aizen Sword (Mythical Rarity)

If you want the Aizen Sword, the Aizen Trainer NPC in Hueco Mundo asks for:

• 3x Reiatsu Cores
• 10x Mirage Pendants
• 6x Illusion Prisms
• 1x Hogyoku Fragment
• 10K Gems
• 6 million Gold

After gathering these items, you unlock the quest, and upon completion, you’re rewarded with the Aizen Sword. The quests are as follows:

• Quest 1
  • Defeat 250 Hollows
• Quest 2
  • Unlock the Shinigami race (has a 1% chance to drop with Race Rerolls)
• Quest 3
  • Use a Worthiness Fragment (drops from Hollows)
    • There is a 25% chance for this quest to fail
• Quest 4
  • Deal a total of 350 million DMG
• Quest 5
  • Defeat the Aizen boss 15 times

True Aizen

The Aizen Sword is a requirement to obtain the stronger option, True Aizen. Only one Aizen Sword is needed for this crafting recipe from the True Aizen Trainer NPC at Soul Society.

It’s important to note that the True Aizen boss does not drop Reiatsu Cores, so battling against him is not necessary. While I’m on the topic, here’s what True Aizen has a chance to drop:

• Fusion Ring
  • 9.5% to 15% drop chance
• Divinity Essence
  • 3.25% to 5% drop chance
• Manipulator Outfit
  • 0.85% to 1.4% drop chance
• Transcendant Core
  • 0.8% to 1.25% drop chance
• Evolution Fragment
  • 0.4% to 0.75% drop chance
• Transcendant Being (Title)
  • 0.75% to 1.35% drop chance

To summon the True Aizen boss, you need the Chrysalis Sigil item.

Adele Wilson

Editor

With experience working for GameRant and in SEO copywriting, Adele loves to combine her adoration for gaming with her writing craft. She'll talk your ear off about anything fantasy, and if she's not typing away at her desk, she's probably playing an RPG somewhere, watching anime, or reading a book.