Deal with the Devil

Ellie agrees to engage in regular conversation with the devil currently known as and henceforth referred to by the name of Koakuma and, at Koakuma's request but no more often than once per day, to assist in performing, or to perform herself, a practical joke upon at least one resident of the House of Scarlet, which is intended by both Ellie and Koakuma to not result in permanent physical, mental, magical or emotional harm for any involved parties.

For each practical joke Ellie assists with or performs, Koakuma agrees to provide one additional personal insight into the abilities, behaviours, motivations and/or histories of the House of Scarlet's inhabitants, as requested by Ellie.

The contract will last until both Ellie and Koakuma agree to end it, or either Ellie or Remilia decide that Ellie should permanently leave the House of Scarlet.