Step 1. Be sure to log in to your account on Legion.
Step 2. Open the "Settings" section.
Step 3. Find the "Connected Accounts" tab.
Step 4. Click on the "Unlink Twitter" button.
Step 5. Back to your Twitter account and open the "Settings" section.
Step 6. Find the "Security and Account access" section.
Step 7. Open the "Apps and Sessions" tab.
Step 8. Click on the "Connected apps" button.
Step 9. Be sure to find Legion there.
Step 10. Click on the "Revoke app permissions" button.
Done!