diff --git a/assets/app.js b/assets/app.js
index ca0f83b..b9b938e 100644
--- a/assets/app.js
+++ b/assets/app.js
@@ -42,6 +42,16 @@ function columnFromTh(th, rowUrl) {
             const short = s.length > 70 ? s.slice(0, 70) + '…' : s;
             return `<span title="${esc(s)}">${esc(short)}</span>`;
         };
+    } else if (th.dataset.format === 'pick') {
+        // a row-select checkbox + quantity, for "add these to the tracker"
+        col.render = (val, type, row) => {
+            if (type !== 'display') return '';
+            return `<span class="track-pick d-inline-flex align-items-center gap-2">
+                <input type="checkbox" class="form-check-input track-check" value="${esc(row.id)}" aria-label="Select">
+                <input type="number" class="form-control form-control-sm track-qty" value="1" min="1" max="50"
+                       style="width: 3.75rem" aria-label="Count">
+            </span>`;
+        };
     } else {
         col.render = (val, type) => (type === 'display' ? esc(val) : (val ?? ''));
     }
diff --git a/assets/controllers/tracker_picker_controller.js b/assets/controllers/tracker_picker_controller.js
new file mode 100644
index 0000000..9c9d879
--- /dev/null
+++ b/assets/controllers/tracker_picker_controller.js
@@ -0,0 +1,41 @@
+import { Controller } from '@hotwired/stimulus';
+
+/*
+ * Collects the ticked rows (+ their quantity) from a DataTable and POSTs them
+ * to the combat tracker.
+ *
+ *   <div data-controller="tracker-picker"
+ *        data-tracker-picker-url-value="/tracker/add"
+ *        data-tracker-picker-token-value="...">
+ *     <button data-action="tracker-picker#submit">Add to tracker</button>
+ *   </div>
+ */
+export default class extends Controller {
+    static values = { url: String, token: String };
+
+    submit() {
+        const picks = [...document.querySelectorAll('.track-check:checked')].map((cb) => {
+            const qtyEl = cb.closest('.track-pick')?.querySelector('.track-qty');
+            const qty = Math.max(1, Math.min(50, parseInt(qtyEl?.value ?? '1', 10) || 1));
+            return { id: cb.value, qty };
+        });
+
+        if (picks.length === 0) {
+            window.alert('Tick at least one enemy first.');
+            return;
+        }
+
+        const form = document.createElement('form');
+        form.method = 'post';
+        form.action = this.urlValue;
+        form.insertAdjacentHTML('beforeend',
+            `<input type="hidden" name="_token" value="${this.tokenValue}">`);
+        picks.forEach((p, i) => {
+            form.insertAdjacentHTML('beforeend',
+                `<input type="hidden" name="picks[${i}][id]" value="${p.id}">` +
+                `<input type="hidden" name="picks[${i}][qty]" value="${p.qty}">`);
+        });
+        document.body.appendChild(form);
+        form.requestSubmit();
+    }
+}
diff --git a/migrations/Version20260906171352.php b/migrations/Version20260906171352.php
new file mode 100644
index 0000000..af8cff9
--- /dev/null
+++ b/migrations/Version20260906171352.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20260906171352 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Create combatant table (running HP tracker)';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('CREATE TABLE combatant (id INT AUTO_INCREMENT NOT NULL, label VARCHAR(120) NOT NULL, max_hp SMALLINT NOT NULL, current_hp SMALLINT NOT NULL, position SMALLINT NOT NULL, added_at DATETIME NOT NULL, enemy_id INT DEFAULT NULL, INDEX IDX_807DA381900C982F (enemy_id), PRIMARY KEY (id)) DEFAULT CHARACTER SET utf8mb4 ENGINE = InnoDB');
+        $this->addSql('ALTER TABLE combatant ADD CONSTRAINT FK_807DA381900C982F FOREIGN KEY (enemy_id) REFERENCES enemy (id) ON DELETE SET NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE combatant DROP FOREIGN KEY FK_807DA381900C982F');
+        $this->addSql('DROP TABLE combatant');
+    }
+}
diff --git a/src/Controller/TrackerController.php b/src/Controller/TrackerController.php
new file mode 100644
index 0000000..24b10d6
--- /dev/null
+++ b/src/Controller/TrackerController.php
@@ -0,0 +1,108 @@
+<?php
+
+namespace App\Controller;
+
+use App\Entity\Combatant;
+use App\Repository\CombatantRepository;
+use App\Repository\EnemyRepository;
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+#[IsGranted('IS_AUTHENTICATED_FULLY')]
+class TrackerController extends AbstractController
+{
+    #[Route('/tracker', name: 'app_tracker', methods: ['GET'])]
+    public function index(CombatantRepository $repo): Response
+    {
+        return $this->render('tracker/index.html.twig', [
+            'combatants' => $repo->tracker(),
+        ]);
+    }
+
+    /**
+     * Add selected enemies (with quantities) from the enemy list to the tracker.
+     * Body: picks[i][id], picks[i][qty].
+     */
+    #[Route('/tracker/add', name: 'app_tracker_add', methods: ['POST'])]
+    public function add(Request $request, EnemyRepository $enemies, CombatantRepository $repo, EntityManagerInterface $em): Response
+    {
+        if (!$this->isCsrfTokenValid('track-add', (string) $request->request->get('_token'))) {
+            return $this->redirectToRoute('app_enemies');
+        }
+
+        $pos = $repo->nextPosition();
+        $added = 0;
+        foreach ($request->request->all('picks') as $pick) {
+            $enemy = isset($pick['id']) ? $enemies->find((int) $pick['id']) : null;
+            if (!$enemy) {
+                continue;
+            }
+            $qty = max(1, min(50, (int) ($pick['qty'] ?? 1)));
+            $existing = $repo->countFromEnemy($enemy);
+
+            for ($i = 1; $i <= $qty; ++$i) {
+                $n = $existing + $i;
+                $label = ($existing + $qty > 1) ? sprintf('%s %d', $enemy->getName(), $n) : $enemy->getName();
+
+                $c = (new Combatant())
+                    ->setEnemy($enemy)
+                    ->setLabel($label)
+                    ->setMaxHp($enemy->getHitPoints())
+                    ->setCurrentHp($enemy->getHitPoints())
+                    ->setPosition($pos++);
+                $em->persist($c);
+                ++$added;
+            }
+        }
+        $em->flush();
+
+        if ($added) {
+            $this->addFlash('success', sprintf('Added %d combatant%s to the tracker.', $added, 1 === $added ? '' : 's'));
+        }
+
+        return $this->redirectToRoute('app_tracker');
+    }
+
+    #[Route('/tracker/{id}/hp', name: 'app_tracker_hp', requirements: ['id' => '\d+'], methods: ['POST'])]
+    public function hp(Request $request, Combatant $combatant, EntityManagerInterface $em): Response
+    {
+        $amount = abs((int) $request->request->get('amount', 0));
+        if ($amount > 0) {
+            'heal' === $request->request->get('mode')
+                ? $combatant->applyHealing($amount)
+                : $combatant->applyDamage($amount);
+            $em->flush();
+        }
+
+        return $this->redirectToRoute('app_tracker');
+    }
+
+    #[Route('/tracker/{id}/remove', name: 'app_tracker_remove', requirements: ['id' => '\d+'], methods: ['POST'])]
+    public function remove(Request $request, Combatant $combatant, EntityManagerInterface $em): Response
+    {
+        if ($this->isCsrfTokenValid('tracker-op', (string) $request->request->get('_token'))) {
+            $em->remove($combatant);
+            $em->flush();
+        }
+
+        return $this->redirectToRoute('app_tracker');
+    }
+
+    #[Route('/tracker/clear', name: 'app_tracker_clear', methods: ['POST'])]
+    public function clear(Request $request, CombatantRepository $repo, EntityManagerInterface $em): Response
+    {
+        if ($this->isCsrfTokenValid('tracker-op', (string) $request->request->get('_token'))) {
+            foreach ($repo->findAll() as $c) {
+                $em->remove($c);
+            }
+            $em->flush();
+            $this->addFlash('success', 'Tracker cleared.');
+        }
+
+        return $this->redirectToRoute('app_tracker');
+    }
+}
diff --git a/src/Entity/Combatant.php b/src/Entity/Combatant.php
new file mode 100644
index 0000000..a3115a3
--- /dev/null
+++ b/src/Entity/Combatant.php
@@ -0,0 +1,140 @@
+<?php
+
+namespace App\Entity;
+
+use App\Repository\CombatantRepository;
+use Doctrine\DBAL\Types\Types;
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * One line on the running combat HP tracker. Stats are copied from the Enemy
+ * when added, so editing the Enemy mid-fight doesn't change the tracker.
+ */
+#[ORM\Entity(repositoryClass: CombatantRepository::class)]
+#[ORM\Table(name: 'combatant')]
+class Combatant
+{
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column]
+    private ?int $id = null;
+
+    #[ORM\ManyToOne(targetEntity: Enemy::class)]
+    #[ORM\JoinColumn(name: 'enemy_id', onDelete: 'SET NULL', nullable: true)]
+    private ?Enemy $enemy = null;
+
+    #[ORM\Column(length: 120)]
+    private string $label = '';
+
+    #[ORM\Column(type: Types::SMALLINT)]
+    private int $maxHp = 1;
+
+    #[ORM\Column(type: Types::SMALLINT)]
+    private int $currentHp = 1;
+
+    #[ORM\Column(type: Types::SMALLINT)]
+    private int $position = 0;
+
+    #[ORM\Column(type: Types::DATETIME_IMMUTABLE)]
+    private \DateTimeImmutable $addedAt;
+
+    public function __construct()
+    {
+        $this->addedAt = new \DateTimeImmutable();
+    }
+
+    public function isDown(): bool
+    {
+        return $this->currentHp <= 0;
+    }
+
+    /** 0-100, for the HP bar. */
+    public function hpPercent(): int
+    {
+        if ($this->maxHp <= 0) {
+            return 0;
+        }
+
+        return (int) round(max(0, min($this->currentHp, $this->maxHp)) / $this->maxHp * 100);
+    }
+
+    public function applyDamage(int $amount): void
+    {
+        $this->currentHp = max(0, $this->currentHp - abs($amount));
+    }
+
+    public function applyHealing(int $amount): void
+    {
+        $this->currentHp = min($this->maxHp, $this->currentHp + abs($amount));
+    }
+
+    public function getId(): ?int
+    {
+        return $this->id;
+    }
+
+    public function getEnemy(): ?Enemy
+    {
+        return $this->enemy;
+    }
+
+    public function setEnemy(?Enemy $enemy): static
+    {
+        $this->enemy = $enemy;
+
+        return $this;
+    }
+
+    public function getLabel(): string
+    {
+        return $this->label;
+    }
+
+    public function setLabel(string $label): static
+    {
+        $this->label = $label;
+
+        return $this;
+    }
+
+    public function getMaxHp(): int
+    {
+        return $this->maxHp;
+    }
+
+    public function setMaxHp(int $maxHp): static
+    {
+        $this->maxHp = $maxHp;
+
+        return $this;
+    }
+
+    public function getCurrentHp(): int
+    {
+        return $this->currentHp;
+    }
+
+    public function setCurrentHp(int $currentHp): static
+    {
+        $this->currentHp = $currentHp;
+
+        return $this;
+    }
+
+    public function getPosition(): int
+    {
+        return $this->position;
+    }
+
+    public function setPosition(int $position): static
+    {
+        $this->position = $position;
+
+        return $this;
+    }
+
+    public function getAddedAt(): \DateTimeImmutable
+    {
+        return $this->addedAt;
+    }
+}
diff --git a/src/Repository/CombatantRepository.php b/src/Repository/CombatantRepository.php
new file mode 100644
index 0000000..c4cd882
--- /dev/null
+++ b/src/Repository/CombatantRepository.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Repository;
+
+use App\Entity\Combatant;
+use App\Entity\Enemy;
+use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\Persistence\ManagerRegistry;
+
+/**
+ * @extends ServiceEntityRepository<Combatant>
+ */
+class CombatantRepository extends ServiceEntityRepository
+{
+    public function __construct(ManagerRegistry $registry)
+    {
+        parent::__construct($registry, Combatant::class);
+    }
+
+    /** @return list<Combatant> */
+    public function tracker(): array
+    {
+        return $this->findBy([], ['position' => 'ASC', 'id' => 'ASC']);
+    }
+
+    public function nextPosition(): int
+    {
+        return 1 + (int) $this->createQueryBuilder('c')
+            ->select('COALESCE(MAX(c.position), 0)')
+            ->getQuery()->getSingleScalarResult();
+    }
+
+    /** How many combatants already come from this enemy (for numbering). */
+    public function countFromEnemy(Enemy $enemy): int
+    {
+        return (int) $this->count(['enemy' => $enemy]);
+    }
+}
diff --git a/templates/base.html.twig b/templates/base.html.twig
index eaf10bd..529f370 100644
--- a/templates/base.html.twig
+++ b/templates/base.html.twig
@@ -30,6 +30,7 @@
                             { route: 'app_characters', label: 'Characters' },
                             { route: 'app_npcs',      label: "NPC's" },
                             { route: 'app_enemies',   label: 'Enemies' },
+                            { route: 'app_tracker',   label: 'Tracker' },
                             { route: 'app_art',       label: 'Art' },
                             { route: 'app_storyline', label: 'Storyline' },
                         ] %}
diff --git a/templates/enemy/index.html.twig b/templates/enemy/index.html.twig
index 1252871..d903b33 100644
--- a/templates/enemy/index.html.twig
+++ b/templates/enemy/index.html.twig
@@ -3,9 +3,17 @@
 {% block title %}Enemies · dmtools{% endblock %}
 
 {% block body %}
-    <div class="d-flex justify-content-between align-items-center mb-3">
+    <div class="d-flex justify-content-between align-items-center mb-3 gap-2 flex-wrap">
         <h1 class="h3 mb-0">Enemies</h1>
-        <a href="{{ path('app_enemies_new') }}" class="btn btn-primary btn-sm">Add enemy</a>
+        <div class="d-flex gap-2"
+             data-controller="tracker-picker"
+             data-tracker-picker-url-value="{{ path('app_tracker_add') }}"
+             data-tracker-picker-token-value="{{ csrf_token('track-add') }}">
+            <button type="button" class="btn btn-outline-primary btn-sm" data-action="tracker-picker#submit">
+                Add to tracker
+            </button>
+            <a href="{{ path('app_enemies_new') }}" class="btn btn-primary btn-sm">Add enemy</a>
+        </div>
     </div>
 
     <div class="card shadow-sm">
@@ -22,6 +30,7 @@
                         <th data-data="challengeRating">CR</th>
                         <th data-data="armorClass">AC</th>
                         <th data-data="gameNotes" data-format="truncate" data-orderable="false">Game notes</th>
+                        <th data-data="id" data-format="pick" data-orderable="false">Track</th>
                     </tr>
                 </thead>
                 <tbody></tbody>
diff --git a/templates/tracker/index.html.twig b/templates/tracker/index.html.twig
new file mode 100644
index 0000000..d8d289d
--- /dev/null
+++ b/templates/tracker/index.html.twig
@@ -0,0 +1,81 @@
+{% extends 'base.html.twig' %}
+
+{% block title %}Tracker · dmtools{% endblock %}
+
+{% block body %}
+    <div class="d-flex justify-content-between align-items-center mb-3 gap-2 flex-wrap">
+        <h1 class="h3 mb-0">Combat tracker
+            {% if combatants %}<span class="text-body-secondary fs-6">· {{ combatants|length }}</span>{% endif %}
+        </h1>
+        <div class="d-flex gap-2">
+            <a href="{{ path('app_enemies') }}" class="btn btn-outline-secondary btn-sm">Add from Enemies</a>
+            {% if combatants %}
+                <form method="post" action="{{ path('app_tracker_clear') }}"
+                      onsubmit="return confirm('Clear the whole tracker?')">
+                    <input type="hidden" name="_token" value="{{ csrf_token('tracker-op') }}">
+                    <button class="btn btn-outline-danger btn-sm">Clear all</button>
+                </form>
+            {% endif %}
+        </div>
+    </div>
+
+    {% if not combatants %}
+        <div class="card shadow-sm">
+            <div class="card-body text-center text-body-secondary py-5">
+                No combatants yet. Go to <strong>Enemies</strong>, tick the ones you want (set a count for
+                multiples), and choose <strong>Add to tracker</strong>.
+            </div>
+        </div>
+    {% else %}
+        <div class="d-flex flex-column gap-2">
+            {% for c in combatants %}
+                {% set pct = c.hpPercent %}
+                {% set bar = c.isDown ? 'bg-secondary' : (pct <= 25 ? 'bg-danger' : (pct <= 50 ? 'bg-warning' : 'bg-success')) %}
+                <div class="card shadow-sm {{ c.isDown ? 'opacity-75' : '' }}">
+                    <div class="card-body py-2">
+                        <div class="row align-items-center g-2">
+                            <div class="col-12 col-md-4">
+                                <div class="fw-semibold {{ c.isDown ? 'text-decoration-line-through' : '' }}">
+                                    {{ c.label }}
+                                    {% if c.isDown %}<span class="badge text-bg-secondary ms-1">Down</span>{% endif %}
+                                </div>
+                                {% if c.enemy %}
+                                    <a href="{{ path('app_enemies_show', {id: c.enemy.id}) }}"
+                                       class="small text-decoration-none text-body-secondary">stat block</a>
+                                {% endif %}
+                            </div>
+
+                            <div class="col-12 col-md-4">
+                                <div class="d-flex align-items-center gap-2">
+                                    <span class="font-monospace" style="min-width: 5rem;">
+                                        <span class="fs-5 fw-semibold">{{ c.currentHp }}</span> / {{ c.maxHp }}
+                                    </span>
+                                    <div class="progress flex-grow-1" role="progressbar" style="height: 10px;">
+                                        <div class="progress-bar {{ bar }}" style="width: {{ pct }}%"></div>
+                                    </div>
+                                </div>
+                            </div>
+
+                            <div class="col-12 col-md-4">
+                                <div class="d-flex align-items-center gap-1 justify-content-md-end flex-wrap">
+                                    <form method="post" action="{{ path('app_tracker_hp', {id: c.id}) }}"
+                                          class="d-flex align-items-center gap-1">
+                                        <input type="number" name="amount" min="0" inputmode="numeric"
+                                               class="form-control form-control-sm" style="width: 4.5rem;"
+                                               placeholder="HP" aria-label="Amount">
+                                        <button name="mode" value="damage" class="btn btn-sm btn-outline-danger">Damage</button>
+                                        <button name="mode" value="heal" class="btn btn-sm btn-outline-success">Heal</button>
+                                    </form>
+                                    <form method="post" action="{{ path('app_tracker_remove', {id: c.id}) }}">
+                                        <input type="hidden" name="_token" value="{{ csrf_token('tracker-op') }}">
+                                        <button class="btn btn-sm btn-outline-secondary" title="Remove" aria-label="Remove">&times;</button>
+                                    </form>
+                                </div>
+                            </div>
+                        </div>
+                    </div>
+                </div>
+            {% endfor %}
+        </div>
+    {% endif %}
+{% endblock %}