The Spectre is the Spirit of Vengeance but he sides with an evil Superman to take over the world to protect it from itself. When Boston Brand AKA Deadman demands to speak to the spirit’s human host Jim Corrigan, the Spectre smiles menacingly. Deadman realizes too late this isn’t his friend. The Spectre kills Deadman by slashing him with a supernatural sword in Injustice: Gods Among Us: Year Three #10.
It’s possible Corrigan is no longer part of the Spectre but that wouldn’t explain the smile. The Spectre naturally lacks compassion but he’s not malicious. This suggests a new host is influencing him. Then again, maybe it’s not even the Spectre. The original Spirit of Vengeance was the supervillain Eclipso, who frequently grins like a madman. In fact, Eclipso killed the Spectre and stole his powers in Justice League of America: The Rise of Eclipso.
Before Deadman passes on, he returns to the Goddess Rama Kushna, who recruited him as her supernatural champion. She allows him to choose his successor: Dick Grayson AKA Nightwing. Damian Wayne AKA Robin accidentally killed Nightwing. Robin agreed with Superman that they should kill supervillains. In a fit of rage Robin threw his nightstick at Nighwing, who fell and snapped his neck. Nightwing is the perfect choice to replace Deadman. Dick was an acrobat like Boston so he’ll be able to handle himself regardless of whom he possesses. He also has a upbeat attitude, which is a must when you can never again interact with anyone except by possession. Dick will surely use his new-found powers to infiltrate team Superman and tell Damian that he forgives him… after a good thrashing of course.