diff --git a/src/en/atsumaru/build.gradle b/src/en/atsumaru/build.gradle
new file mode 100644
index 000000000..1ca955c27
--- /dev/null
+++ b/src/en/atsumaru/build.gradle
@@ -0,0 +1,8 @@
+ext {
+    extName = 'Atsumaru'
+    extClass = '.Atsumaru'
+    extVersionCode = 1
+    isNsfw = true
+}
+
+apply from: "$rootDir/common.gradle"
diff --git a/src/en/atsumaru/res/mipmap-hdpi/ic_launcher.png b/src/en/atsumaru/res/mipmap-hdpi/ic_launcher.png
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diff --git a/src/en/atsumaru/res/mipmap-xhdpi/ic_launcher.png b/src/en/atsumaru/res/mipmap-xhdpi/ic_launcher.png
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diff --git a/src/en/atsumaru/res/mipmap-xxxhdpi/ic_launcher.png b/src/en/atsumaru/res/mipmap-xxxhdpi/ic_launcher.png
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diff --git a/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Atsumaru.kt b/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Atsumaru.kt
new file mode 100644
index 000000000..8d7a5b55e
--- /dev/null
+++ b/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Atsumaru.kt
@@ -0,0 +1,156 @@
+package eu.kanade.tachiyomi.extension.en.atsumaru
+
+import eu.kanade.tachiyomi.network.GET
+import eu.kanade.tachiyomi.network.interceptor.rateLimit
+import eu.kanade.tachiyomi.source.model.FilterList
+import eu.kanade.tachiyomi.source.model.MangasPage
+import eu.kanade.tachiyomi.source.model.Page
+import eu.kanade.tachiyomi.source.model.SChapter
+import eu.kanade.tachiyomi.source.model.SManga
+import eu.kanade.tachiyomi.source.online.HttpSource
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.json.Json
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import okhttp3.Request
+import okhttp3.Response
+import uy.kohesive.injekt.injectLazy
+
+class Atsumaru : HttpSource() {
+
+    override val name = "Atsumaru"
+
+    override val baseUrl = "https://atsu.moe"
+    private val apiUrl = "$baseUrl/api/v1"
+
+    override val lang = "en"
+
+    override val supportsLatest = true
+
+    override val client = network.cloudflareClient.newBuilder()
+        .rateLimit(2)
+        .build()
+
+    override fun headersBuilder() = super.headersBuilder()
+        .add("Referer", "$baseUrl/")
+
+    private fun apiHeadersBuilder() = headersBuilder().apply {
+        add("Accept", "*/*")
+        add("Host", apiUrl.toHttpUrl().host)
+    }
+
+    private val apiHeaders by lazy { apiHeadersBuilder().build() }
+
+    private val json: Json by injectLazy()
+
+    // ============================== Popular ===============================
+
+    override fun popularMangaRequest(page: Int): Request {
+        return GET("$apiUrl/layouts/s1/sliders/hotUpdates", apiHeaders)
+    }
+
+    override fun popularMangaParse(response: Response): MangasPage {
+        val data = response.parseAs<BrowseMangaDto>().items
+
+        return MangasPage(data.map { it.manga.toSManga() }, false)
+    }
+
+    // =============================== Latest ===============================
+
+    override fun latestUpdatesRequest(page: Int): Request {
+        return GET("$apiUrl/layouts/s1/latest-updates", apiHeaders)
+    }
+
+    override fun latestUpdatesParse(response: Response): MangasPage {
+        return popularMangaParse(response)
+    }
+
+    // =============================== Search ===============================
+
+    override fun searchMangaRequest(page: Int, query: String, filters: FilterList): Request {
+        val url = "$apiUrl/search".toHttpUrl().newBuilder()
+            .addPathSegment(query)
+            .build()
+
+        return GET(url, apiHeaders)
+    }
+
+    override fun searchMangaParse(response: Response): MangasPage {
+        val data = response.parseAs<SearchResultsDto>().hits
+
+        return MangasPage(data.map { it.info.toSManga() }, false)
+    }
+
+    // =========================== Manga Details ============================
+
+    override fun getMangaUrl(manga: SManga): String {
+        return baseUrl + manga.url
+    }
+
+    override fun mangaDetailsRequest(manga: SManga): Request {
+        return GET(apiUrl + manga.url, apiHeaders)
+    }
+
+    override fun mangaDetailsParse(response: Response): SManga {
+        return response.parseAs<MangaObjectDto>().manga.toSManga()
+    }
+
+    // ============================== Chapters ==============================
+
+    override fun chapterListRequest(manga: SManga): Request {
+        return mangaDetailsRequest(manga)
+    }
+
+    override fun chapterListParse(response: Response): List<SChapter> {
+        val chapterList = response.parseAs<MangaObjectDto>().manga.chapters!!.map {
+            it.toSChapter(response.request.url.pathSegments.last())
+        }
+
+        return chapterList.sortedWith(
+            compareBy(
+                { it.chapter_number },
+                { it.scanlator },
+            ),
+        ).reversed()
+    }
+
+    override fun getChapterUrl(chapter: SChapter): String {
+        val (slug, name) = chapter.url.split("/")
+        return "$baseUrl/read/s1/$slug/$name/1"
+    }
+
+    // =============================== Pages ================================
+
+    override fun pageListRequest(chapter: SChapter): Request {
+        val (slug, name) = chapter.url.split("/")
+        return GET("$apiUrl/manga/s1/$slug#$name", apiHeaders)
+    }
+
+    override fun pageListParse(response: Response): List<Page> {
+        val chapter = response.parseAs<MangaObjectDto>().manga.chapters!!.first {
+            it.name == response.request.url.fragment
+        }
+
+        return chapter.pages.map { page ->
+            Page(page.name.toInt(), imageUrl = page.pageURLs.first())
+        }.sortedBy { it.index }
+    }
+
+    override fun imageRequest(page: Page): Request {
+        val imgHeaders = headersBuilder().apply {
+            add("Accept", "image/avif,image/webp,*/*")
+            add("Host", page.imageUrl!!.toHttpUrl().host)
+        }.build()
+
+        return GET(page.imageUrl!!, imgHeaders)
+    }
+
+    override fun imageUrlParse(response: Response): String {
+        throw UnsupportedOperationException()
+    }
+
+    // ============================= Utilities ==============================
+
+    private inline fun <reified T> Response.parseAs(): T {
+        return json.decodeFromString(body.string())
+    }
+}
diff --git a/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Dto.kt b/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Dto.kt
new file mode 100644
index 000000000..5928fdeb7
--- /dev/null
+++ b/src/en/atsumaru/src/eu/kanade/tachiyomi/extension/en/atsumaru/Dto.kt
@@ -0,0 +1,115 @@
+package eu.kanade.tachiyomi.extension.en.atsumaru
+
+import eu.kanade.tachiyomi.source.model.SChapter
+import eu.kanade.tachiyomi.source.model.SManga
+import kotlinx.serialization.Serializable
+import java.text.ParseException
+import java.text.SimpleDateFormat
+import java.util.Locale
+
+@Serializable
+class BrowseMangaDto(
+    val items: List<MangaObjectDto>,
+)
+
+@Serializable
+class MangaObjectDto(
+    val manga: MangaDto,
+)
+
+@Serializable
+class SearchResultsDto(
+    val hits: List<SearchMangaDto>,
+) {
+    @Serializable
+    class SearchMangaDto(
+        val info: MangaDto,
+    )
+}
+
+@Serializable
+class MangaDto(
+    // Common
+    private val title: String,
+    private val cover: String,
+    private val slug: String,
+
+    // Details
+    private val authors: List<String>? = null,
+    private val description: String? = null,
+    private val genres: List<String>? = null,
+    private val statuses: List<String>? = null,
+
+    // Chapters
+    val chapters: List<ChapterDto>? = null,
+) {
+    fun toSManga(): SManga = SManga.create().apply {
+        title = this@MangaDto.title
+        thumbnail_url = cover
+        url = "/manga/s1/$slug"
+
+        authors?.let {
+            author = it.joinToString()
+        }
+        description = this@MangaDto.description
+        genres?.let {
+            genre = it.joinToString()
+        }
+        statuses?.let {
+            status = when (it.first().lowercase().substringBefore(" ")) {
+                "ongoing" -> SManga.ONGOING
+                "complete" -> SManga.COMPLETED
+                else -> SManga.UNKNOWN
+            }
+        }
+    }
+}
+
+@Serializable
+class ChapterDto(
+    val pages: List<PageDto>,
+    val name: String,
+    private val type: String,
+    private val title: String? = null,
+    private val date: String? = null,
+) {
+    fun toSChapter(slug: String): SChapter = SChapter.create().apply {
+        val chapterNumber = this@ChapterDto.name.replace("_", ".")
+            .filter { it.isDigit() || it == '.' }
+
+        name = buildString {
+            append("Chapter ")
+            append(chapterNumber)
+            if (title != null) {
+                append(" - ")
+                append(title)
+            }
+        }
+        url = "$slug/${this@ChapterDto.name}"
+        chapter_number = chapterNumber.toFloat()
+        scanlator = type.takeUnless { it == "Chapter" }
+        date?.let {
+            date_upload = parseDate(it)
+        }
+    }
+
+    private fun parseDate(dateStr: String): Long {
+        return try {
+            DATE_FORMAT.parse(dateStr)!!.time
+        } catch (_: ParseException) {
+            0L
+        }
+    }
+
+    companion object {
+        private val DATE_FORMAT by lazy {
+            SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.ENGLISH)
+        }
+    }
+}
+
+@Serializable
+class PageDto(
+    val pageURLs: List<String>,
+    val name: String,
+)