Legacy Piece Ancient Infernal Core: How to Get and Use It

What it is for

The Ancient Infernal Core is not a crafting material. The official board mentions it exactly once, on the Benimaru card, as part of the summon recipe for the Demon Infernal world boss:

One core, one summon. If you are working toward Benimaru, every core you own is one shot at the King of Asakusa title and the Duo Matoi / Sun Wheel / Benimaro’s Eyes materials — see the Fire Force guide for the full bill.

Where it comes from

The board’s materials list has no card for it, so the drop source is not published there. Two community guides publish the in-game Infernal Ambusher drop card, and both list the same figure:

At 15% you should see a core roughly every seven Ambusher kills, and the Ambusher is a fight you trigger on demand at the ambush points rather than something you wait for. The code is the free one — it was still active at the last check on the codes page, and it also covers the 30 tickets the summon needs many times over.

What the summon gives you

Demon Infernal is the source of everything Benimaru needs that the Ambusher does not drop:

• King of Asakusa title (required for Benimaru)
• Duo Matoi, Sun Wheel, Benimaro’s Eyes
• Ember Fragment and Infernal Core, shared with the Ambusher
• Starlight Shards at 8.33% while Stardust 3 of the Star Platinum questline is active

The board’s Demon Infernal boss card carries no drop table yet, so the percentages for the Benimaru materials are not published — only the sources above. World bosses do refund Boss Tickets at 45% per kill on both documented cards, which is what keeps a 30-ticket summon affordable; see the world boss guide.

A farm order that does not waste cores

1. Run the Infernal Ambusher first. It drops Ember Fragment and Infernal Core for both specs, the core for the summon, and Shinra’s exclusive materials.
2. Bank tickets — codes, the 45% world-boss refund, and the Iron ×15 + 50,000 Money craft if you run short.
3. Summon Demon Infernal only at a difficulty you can clear; the summon modes from 1.5 Part 2 scale the cost of every ingredient, the core included.
4. Buy the last few of any Benimaru material from the Fire Fighter Company Shop instead of spending another core on it.