charasheet/src/character/templates/character/snippets/character_details/damage_reduction_update.html

<form id="damage-reduction">
    <div class="card">
        <h5 class="card-header">
            Réduction de dégâts
            <a hx-post="{% url "character:damage_reduction_change" pk=character.pk %}"
               hx-target="#damage-reduction"
               hx-swap="outerHTML"
               class="btn btn-primary btn-sm"
            >
                <i class="fa-solid fa-save"></i> Save
            </a>
        </h5>
        <div class="card-body">
            {% csrf_token %}
            <textarea class="form-control" name="damage_reduction" rows="2">{{ character.damage_reduction }}</textarea>
        </div>
    </div>
</form>