Final answer:
Eret was crowned King of Greater Dream SMP after betraying L'Manberg during the First War, a role-played conflict in the server that involves detailed storytelling.
Step-by-step explanation:
The individual who was crowned King of Greater Dream SMP for his involvement in the First War of L'Manburg was Eret. Eret betrayed L'Manburg during the conflict and joined Dream SMP, leading to their title and kingship as a reward for their actions. The Dream SMP is an online role-playing server in the game where players create storylines and engage in political and social battles. The conflict between Dream SMP and L'Manburg is part of an elaborate narrative developed by the server's participants, and the First War of L'Manburg led to intense gameplay and a significant moment in the server's lore.