Centurion. The research half of the associate you didn't hire.
It sits beside every matter and every draft. It finds the cases, checks the citations, and reads the opinions before it quotes them.
Research You Can Open and Read
Centurion is Legion's AI assistant. It sits in a panel beside the case files on every matter, and beside the document on each drafting step.
When you ask for authority, it searches published opinions in CourtListener, the Free Law Project's case-law database. Every case it cites opens inside Legion, with a link to the opinion on CourtListener.
It confirms that a case exists and what it says. Whether the case is still good law stays with you.
How a Citation Check Works
Step 1: Ask
Ask for authority in the panel beside your matter or your draft. Search by party name, subject, or phrase, and narrow by court and date.
Step 2: Search and Look Up
Centurion searches published opinions in CourtListener and looks up each citation it plans to rely on. CourtListener answers whether an opinion exists at that citation, with a link to the case. If CourtListener lacks a case, Centurion searches the web and labels what it finds there as web-sourced and not CourtListener-verified.
Step 3: Read, Then You Verify
Centurion reads the opinions it relies on in full, and any language it quotes must come from that text. Click the case and the opinion opens with the quoted passage highlighted. You read the holding and check treatment in your citator before you sign.
What Centurion Does
Five things, each checked against CourtListener or your own record.
Search
Searches published opinions in CourtListener by party name, subject, or phrase, narrowed by court and date.
Existence check
Checks that every cited case exists in CourtListener and opens it.
Quotes
Quotes only from the opinion's own text, highlighted in the viewer.
Record cites
Reads your record and cites it to the page and line.
Verify every authority
On an MPA, one click verifies every authority and fixes the brief in place.
What Centurion does not check
Centurion confirms that a case exists and what it says. It does not check subsequent history: reversal, depublication, or negative treatment. It tells you so.
That check stays with your citator and your signature.
California's SB 574 (Stats. 2026, ch. 858), effective January 1, 2027, requires attorneys to personally verify the citations they rely on and bars delegating the practice of law to AI. Centurion is built for that split: it finds, confirms, and reads; you verify treatment and sign.
On the Matter
The same panel sits beside the case files on every matter. Ask it to:
- Catch me up
- Build the chronology
- Procedural history
- Spot inconsistencies
- Start a draft from chat
What It Costs
- Inside any draft, Centurion is included.
- On the matter, every matter starts with credit.
- A quick question is usually a few cents. A deep research request can be $20–80.
- You set the per-answer ceiling.
Frequently Asked Questions
Open a Matter. Ask for the Case.
Centurion is on every matter and every drafting step. Bring a matter you're working on and ask it for the authority.
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