Terms of Use

Last updated: July 20, 2026

These Terms of Use ("Terms") govern your use of Derivon ("the App"). By using the App, you agree to these Terms.

1. Eligibility

The App is intended for users aged 13 and older. Users under 13 must obtain parental consent before using the App.

2. Accounts

• You may sign in using your Apple ID or Google account.
• You are responsible for managing your account credentials.
• Please notify us immediately if you discover unauthorized access or suspicious activity.

3. Prohibited Activities

The following activities are prohibited:

• Reverse engineering, tampering with, or gaining unauthorized access to the App
• Using automated tools to collect data
• Engaging in activities that disturb other users
• Any activity that violates applicable laws or public order

4. In-App Purchases

The App offers in-app purchases of "Star Fragments" (consumable items).

• Charges are billed to the account associated with your Apple ID.
• Star Fragments are consumable and cannot be reused once spent.
• Cancellations and refunds after purchase are subject to Apple's policies. The developer does not process refunds directly.
• Parental consent is required for users under 13.
• No compensation will be provided for unused items if the service is discontinued.

5. Subscription (Derivon Super)

The App offers an auto-renewable subscription, "Derivon Super."

• Price: 780 JPY per month / 4,800 JPY per year (tax included). Prices outside Japan follow Apple's regional pricing.
• Benefits: unlimited stamina, no ads, one free treasure box per day, and 5 Star Fragments each month.
• Free trial: 7 days, available only for your first subscription. Not available if you have previously used a trial within the same subscription group.
• Auto-renewal: Unless canceled at least 24 hours before the end of the current period, the subscription renews automatically at the same price and duration. Your Apple ID is charged within 24 hours prior to the end of the current period.
• Cancellation: You may cancel at any time from Settings → Apple ID → Subscriptions on your iPhone. You retain access to the benefits until the end of the paid period.
• Refunds: Subject to Apple's policies. The developer does not process refunds directly.
• All learning content remains free to use, with or without a subscription.

6. In-Game Data

In-game data such as Star Sand, planet progress, and streaks are synced to the cloud. However, we do not guarantee data recovery in the event of connectivity issues or data loss.

7. Service Changes and Termination

We may modify features or discontinue the App without prior notice. No compensation will be provided for in-game data upon service termination.

8. Disclaimer

The App is provided "as is." The developer shall not be liable for any damages arising from the use of the App.

9. Changes to These Terms

These Terms may be updated as needed. Continued use of the App after changes constitutes acceptance of the revised Terms.

10. Contact Us

If you have questions about these Terms, please reach out via our contact form.