=> https://native-jizen.kamihimeproject.net/sp/

jizen.js

var f = function(i) {
    $.ajax({
        url: 'https://api-native-jizen.kamihimeproject.net/csrf',
        dataType: 'json',
        type: 'GET',
        xhrFields: {
            withCredentials: true
        }
    }).done(function(data) {
        $.ajax({
            url: 'https://api-native-jizen.kamihimeproject.net/register-email',
            dataType: "json",
            data: {
                email: 'kilfu0701+' + i + '@gmail.com',
            },
            type: 'POST',
            xhrFields: {
                withCredentials: true
            },
            headers: {
                'HTTP_X_REQUESTED_WITH': 'xmlhttprequest',
                'X-CSRF-TOKEN': data.csrf_token
            },
            success: function(r) {
                console.log('ok', i);
            }
        });
    });
};

var a = 3;
var si = window.setInterval(function() {
    if (a >= 500) {
        window.clearInterval(si);
    }
    f(a);
    a++;
}, 200);