Saleen handed over the giant's skull to the Winged Skull and had them bring it to Nailisi. Saleen had his own thoughts as well. While the cemetery of the giant had been a huge, elaborate trap, it was unknown who it was meant for. However, that giant skull was real. If it actually turned out to be the King of Glory's friend, Saleen's blasphemous actions would mean that he would die a horrible death.
Letting Nailisi have it, be it to have her eat it or put into the 12 Notes of First Purgatory to be broken down, she would destroy it one way or another. Leaving it intact would be like having a sword hanging above his head.
Saleen was known for petty advantages, but he dared not do so anymore. That contract with the Goddess of Myers embroiled him into the conflict between the goddess and the Imperial City of the Abyss, and he had only been doing it to acquire greater power all those years ago.
In hindsight, it was really a sh**ty deal.
