Slayers 2 orbs

No boss is tied to an orb. All 9 art orbs come out of chests, all at the same odds: 2% from a world-boss chest, 1% from a common one. So the Reaper Orb, the Blood Manipulation Orb and the Dream Orb are farmed the same way: kill whatever drops the best chest you can reach, and open it. To check the current list after a patch, open Archives and Evil Art Orbs in your own game.

Archives, tab Evil Art Orbs (9). Reaper Orb, Common, and under Source: 2% from Ice Chest, Rare Chest, Sealed Cache T1, T2, T3 and World Events Chest, 1% from Common Chest and Lost Chest.

At Lv 132, beating Mini Boss Thunder Trainee pays +108 Blood Manipulation Mastery and +10 Demon Progress, and leaves a Reaper Orb with a Claim prompt.

Which chest, which boss

The chance is per orb: a 2% chest gives a 2% shot at a Reaper Orb, and separately at each of the other eight. The chest a boss leaves is printed on its health bar; every boss’s full list is in the boss drop tables.

Chest	Chance per orb	One named orb in 10 chests	Who drops it
`Ice Chest`	2%	18%	Fujiko
`Rare Chest`	2%	18%	Hoyuzo
`Sealed Cache T1`	2%	18%	Not from a known boss
`Sealed Cache T2`	2%	18%	Not from a known boss
`Sealed Cache T3`	2%	18%	Not from a known boss
`World Events Chest`	2%	18%	Obari, Zentaro, Giyen, Saneri, Shinora, Tengai, Rengu, Gyorei, Nezura, Datai, Gyutai, Domae, Akazo, Enru, Sumari, Yahari, Yeti Demon, Reaper
`Common Chest`	1%	10%	Water Trainee Sabito, Stone Trainee, Thunder Trainee, Mother Bear
`Lost Chest`	1%	10%	Not from a known boss

The 10-chest column assumes each chest rolls on its own, with no pity counter.

Best odds

Any of the 18 world bosses: a World Events Chest at 2% per orb, twice the rate of the mini bosses’ Common Chest. The drop calculator works for orbs too: type 2 into its chance box and read off how many kills a coin flip takes.

Where the other chests come from

Every demon boss now has its chest read: a World Events Chest each, except Fujiko’s Ice Chest. Hoyuzo leaves a Rare Chest. Sealed caches reportedly lie around the map, and a Lost Chest may drop after the Lost Slayer in Final Selection.

The 9 orbs and what the game says about each

Names are as the game spells them, including Pyrokenesis. The Ice art’s orb is the Cryokinesis Orb. Every entry is rarity Common and carries the chest list above.

The Archives menu with the Blood Manipulation Orb selected, showing the same source list — The Archives entry for `Blood Manipulation Or…` (the name runs off the panel). The `Source` list under it is identical to the Reaper Orb's.

Blood Manipulation Orb
Starts Blood Manipulation core training · also called blood orb
“Half full of something that moves like blood and settles like it too. Crush it in a demon's hand to open Blood Manipulation core training.”
Dream Orb
Starts Dream Manipulation core training
“A drowsy pulse moves inside. Crush it to open Dream core training, where sleep and flesh take the same shape.”
Obi Manipulation Orb
Starts Obi Manipulation core training
“Something dark and silken coils inside. Squeezing it starts Obi Manipulation core training for an unclaimed demon core.”
Reaper Orb
Starts Reaper core training
“Hollow as a little moon, it opens Reaper core training when squeezed by blood not yet pledged to an art.”
Tamari Orb
Starts Tamari core training
“Warm and oddly heavy in the palm. Crush it to begin Tamari core training.”
Shockwave Orb
Starts Shockwave core training
“Heavy in the palm, this orb starts Shockwave core training when crushed hard enough for the body to answer.”
Arrow Orb
Starts Arrow core training
“Veined glass for an unbound demon core. Squeeze it to start Arrow core training, where force learns hidden direction.”
Pyrokenesis Orb
Starts Pyrokinesis core training · also called Pyrokinesis Orb
“Heat crawls under the shell. Crush it to begin Pyrokenesis core training before the flame leaks away.”
Cryokinesis Orb
Starts Ice Manipulation core training · also called Ice orb
“Frost beads beneath the shell. Squeezing it begins Cryokinesis core training for a core not yet claimed.”

Which of these is worth farming for is a separate question: the art tier lists compare them, and Blood Demon Arts covers each art’s weapon and moves.

From chest to art

An orb does not hand you the art. Crush it to start that art’s core training (every step of one is on the Cryokinesis core page). The loop from start to finish:

1 · Claim it
Kill the boss, open its chest, and walk up to the glowing orb. The prompt is the orb’s name with Claim on the T key. A Thunder Trainee’s chest, for example, can hold a Reaper Orb.
At night, one second before the next frame: an opened chest beside the player, two items on the grass, and the header Mini Boss Thunder Trainee Spawns in 1:56.
2 · Hold it and click
The orb sits on your hotbar. Equip it and click it, and a quest titled <Art> Core Training appears in the tracker. The Shockwave version has 5 steps, in this order: Push ups, Barbell squats, Boulder Push, Boulder Split, Defeat Mizunotos (5).
The minigames are the ones breathing trainers use; the training guide explains each. The other eight arts’ lists may differ.
Shockwave Core Training 0/5: Push ups 0/1, Barbell squats 0/1, Boulder Push 0/1, Boulder Split 0/1, Defeat Mizunotos 0/5, each locked behind the one before. Reward line Exp +900 and Wen +405.
3 · Finish it
With the last step done, the art is yours at mastery level 1. Its further moves open in the skill tree as that mastery climbs, and the codes page lists a free skill-tree reset if you want to redo the points.
Training done: the chat reads You've proven yourself., the pickups +900 Exp and +405 Wen, a Shockwave NEW! notice, and Shockwave Mastery Lv 1 appears bottom right.

Two things that stop an orb

Leaving the server

Orbs from chests do not survive a rejoin: log off and every art orb you hold is gone. Use it in the session you find it.

Already having an art

Clicking an orb while you already have an art only gets My power already runs in you from Muzan, and the orb stays in your inventory. Remove the current art first: Reset Evil Art in the shop, or the free ARTRESET code.

The other route: Muzan’s roll

Orbs are not the only way in. Once you are a demon, Muzan’s Give me your power rolls in his lair, with a 50% chance of nothing; a win hands you the art’s orb, which then needs its core training like any chest orb. Chests are random too, but every boss kill is another roll, and you only crush the orb you actually want. Getting to Muzan at all is covered in how to become a demon and where to find him.