Hi sosbanfawr, while I cannot tell you about any personal experiences of deleting a long-time character I can say that when you delete your Titan you will lose all Progress related to him, including the Moments of Triumphs you've completed with that character. However, losing any MoT Progress will not lock you out of using the Laurea Prima Emblem. Also, Grimoire Progress is not influenced either. Hope this helps. Any more questions, ask away.