diff --git a/userscript/manga-bookmark.user.js b/userscript/manga-bookmark.user.js
index f8ef6ba..027f44e 100644
--- a/userscript/manga-bookmark.user.js
+++ b/userscript/manga-bookmark.user.js
@@ -292,7 +292,86 @@
     },
   };
 
-  const ADAPTERS = [asura, demonic, comix];
+  const kagane = {
+    site: "kagane",
+    matches: (loc) => /(^|\.)kagane\.to$/.test(loc.hostname),
+    detect(loc) {
+      const path = loc.pathname;
+      const UUID = "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}";
+      // /series/<uuid>/reader/<bookUuid> — no chapter number anywhere in the
+      // URL, so it comes out of og:title instead.
+      let m = path.match(new RegExp("^/series/(" + UUID + ")/reader/" + UUID));
+      if (m) {
+        const num = chapterNumFromTitle(meta("og:title"));
+        return {
+          type: "chapter",
+          site: this.site,
+          seriesId: m[1],
+          title: cleanTitle(meta("og:title")),
+          cover: meta("og:image") || "",
+          seriesUrl: loc.origin + "/series/" + m[1],
+          chapterLabel: num === null ? null : "Chapter " + num,
+          chapterNum: num,
+          chapterUrl: loc.href,
+        };
+      }
+      // /series/<uuid>
+      m = path.match(new RegExp("^/series/(" + UUID + ")/?$"));
+      if (m) {
+        return {
+          type: "series",
+          site: this.site,
+          seriesId: m[1],
+          title: cleanTitle(meta("og:title")),
+          cover: meta("og:image") || "",
+          seriesUrl: loc.origin + "/series/" + m[1],
+          chapterLabel: null,
+          chapterNum: null,
+          chapterUrl: null,
+        };
+      }
+      return { type: "other" };
+
+      // Reader og:title is "<Title> - Chapter <n> - <episode name>".
+      function chapterNumFromTitle(t) {
+        const m = t && t.match(/\s-\sChapter\s([\d.]+)\s/);
+        if (!m) return null;
+        const num = parseFloat(m[1]);
+        return isNaN(num) ? null : num;
+      }
+
+      function cleanTitle(t) {
+        if (!t) return "";
+        return t.replace(/\s-\sChapter\s[\d.]+\s-\s.*$/i, "").trim();
+      }
+    },
+    // Reader hrefs are uuids with no number in them, so no maximum can be taken
+    // from anchors at all. latestChapterFromApi replaces this path entirely.
+    latestChapterFromAnchors() {
+      return null;
+    },
+    // Same-origin only: the request needs the Cloudflare clearance cookie that
+    // this browser already holds for kagane.to. Called cross-origin it would be
+    // challenged and return nothing.
+    async latestChapterFromApi(seriesId) {
+      try {
+        const res = await fetch("/api/v2/series/" + seriesId);
+        if (!res.ok) return null;
+        const data = await res.json();
+        let best = null;
+        for (const b of (data && data.series_books) || []) {
+          const num = parseFloat(b.chapter_no);
+          if (isNaN(num)) continue;
+          if (!best || num > best.num) best = { num, label: "Chapter " + b.chapter_no };
+        }
+        return best;
+      } catch (e) {
+        return null;
+      }
+    },
+  };
+
+  const ADAPTERS = [asura, demonic, comix, kagane];
 
   function detect() {
     const loc = window.location;
@@ -1694,7 +1773,7 @@
   // Exposes pure logic only — see userscript/test/logic.test.js.
   // ============================================================
   if (typeof window === "undefined" && typeof module === "object" && module.exports) {
-    module.exports = { stripBuildHash, comixSeriesId, asura, demonic, comix, anchorsFromHTML, statusOf };
+    module.exports = { stripBuildHash, comixSeriesId, asura, demonic, comix, kagane, anchorsFromHTML, statusOf };
   }
 
   // ============================================================
diff --git a/userscript/test/logic.test.js b/userscript/test/logic.test.js
index 7ed1677..f6b96c3 100644
--- a/userscript/test/logic.test.js
+++ b/userscript/test/logic.test.js
@@ -57,6 +57,7 @@ const {
   asura,
   demonic,
   comix,
+  kagane,
   anchorsFromHTML,
   statusOf,
 } = require("../manga-bookmark.user.js");
@@ -274,6 +275,90 @@ test("asura and demonic ignore the seriesId argument", () => {
   });
 });
 
+// ============================================================
+// kagane — reader URLs carry uuids and no chapter number, so the number has to
+// come out of og:title. When that fails, chapterNum is null and the existing
+// progress logic records the current chapter rather than guessing.
+// ============================================================
+
+const KAGANE_SERIES = "019f84bc-9ba0-7ed9-86f5-8b905ec7c28b";
+const KAGANE_BOOK = "019fa2e0-6dbd-73ca-b40b-fe06ab75eb0e";
+
+test("kagane detects a series page", () => {
+  metaTags = {
+    "og:title": "Infinite Decryption: The Strongest Level 0",
+    "og:image": "https://kagane.to/api/v2/image/abc/compressed",
+  };
+  const p = kagane.detect(loc("https://kagane.to/series/" + KAGANE_SERIES));
+  assert.equal(p.type, "series");
+  assert.equal(p.site, "kagane");
+  assert.equal(p.seriesId, KAGANE_SERIES);
+  assert.equal(p.title, "Infinite Decryption: The Strongest Level 0");
+  assert.equal(p.cover, "https://kagane.to/api/v2/image/abc/compressed");
+  assert.equal(p.seriesUrl, "https://kagane.to/series/" + KAGANE_SERIES);
+});
+
+test("kagane reads the chapter number out of og:title", () => {
+  metaTags = {
+    "og:title": "Infinite Decryption: The Strongest Level 0 - Chapter 41 - Episode 41",
+    "og:image": "https://kagane.to/api/v2/image/abc/compressed",
+  };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.type, "chapter");
+  assert.equal(p.seriesId, KAGANE_SERIES);
+  assert.equal(p.title, "Infinite Decryption: The Strongest Level 0");
+  assert.equal(p.chapterNum, 41);
+  assert.equal(p.chapterLabel, "Chapter 41");
+  assert.equal(p.seriesUrl, "https://kagane.to/series/" + KAGANE_SERIES);
+});
+
+test("kagane yields a null chapterNum when og:title has no chapter", () => {
+  metaTags = { "og:title": "Infinite Decryption: The Strongest Level 0" };
+  const p = kagane.detect(
+    loc("https://kagane.to/series/" + KAGANE_SERIES + "/reader/" + KAGANE_BOOK)
+  );
+  assert.equal(p.type, "chapter");
+  assert.equal(p.chapterNum, null);
+});
+
+test("kagane ignores unrelated paths", () => {
+  assert.equal(kagane.detect(loc("https://kagane.to/search")).type, "other");
+});
+
+test("kagane anchor scanning is structurally impossible and returns null", () => {
+  const anchors = anchorsFromHTML(
+    `<a href="/series/${KAGANE_SERIES}/reader/${KAGANE_BOOK}">Chapter 41</a>`
+  );
+  assert.equal(kagane.latestChapterFromAnchors(anchors, KAGANE_SERIES), null);
+});
+
+test("kagane latestChapterFromApi takes the max chapter_no", async () => {
+  globalThis.fetch = async (url) => {
+    assert.equal(url, "/api/v2/series/" + KAGANE_SERIES);
+    return {
+      ok: true,
+      json: async () => ({
+        series_books: [
+          { chapter_no: "1", title: "Episode 1" },
+          { chapter_no: "41", title: "Episode 41" },
+          { chapter_no: "40.5", title: "Episode 40.5" },
+        ],
+      }),
+    };
+  };
+  assert.deepEqual(await kagane.latestChapterFromApi(KAGANE_SERIES), {
+    num: 41,
+    label: "Chapter 41",
+  });
+});
+
+test("kagane latestChapterFromApi returns null on a challenge or error", async () => {
+  globalThis.fetch = async () => ({ ok: false, status: 403 });
+  assert.equal(await kagane.latestChapterFromApi(KAGANE_SERIES), null);
+});
+
 // ============================================================
 // Shared helpers
 // ============================================================