If you liked the Makai Ouji: Devils and Realist anime, the Anime-Planet community thinks you'd like:
In Victorian England it is commonplace for the rich and wealthy to have a staff, led by a head butler, to run their households; the Phantomhive Estate is no different. The young and demanding Count Ciel Phantomhive, child owner of a toy company, lives in the grand countryside manor. Sebastian is his head butler, and the epitome of perfection; he effortlessly and gracefully completes his day-to day chores and fixes the countless mistakes of the other employees. However, whilst on the outside all seems prim and proper, a more sinister secret lies just beneath the surface. Sebastian is in fact a demon bound by a contract with the young count; he will loyally serve and fight for him in return for his soul.
In both Kuroshitsuji and Makai Ouji, both MCs are headstrong young men from wealthy families, have experienced tragedies, and are surrounded by a multitude of good-looking bishie demons. With a touch of comedy and plenty of drama, the similarities between these two shows are hard to miss.
Angels, demons, rich people, and more homoerotic undertones than you shake a stick at. Good in one, good in the other.
On the eve of nobleman Oz Bezarius's fifteenth birthday, he and his loved ones gather to celebrate in a coming-of-age ceremony. But after Oz steps under a long-stopped clock and the hands finally move once more - thus fulfilling a mysterious prophecy - he is violently thrown into the legendary prison known as the Abyss by three cloaked intruders. Existing in another dimension, the Abyss is home to lifeforms born within its walls known as Chains; these beings can only live in the real world if they make contracts with humans, binding their power to the person's body. However, there's a catch - in time, the human will be overcome by the Chain's power and then thrown into the deepest level of the Abyss. When Oz wakes up in the Abyss he is quickly attacked by hungry Chains, only to be saved by one named Alice - a Chain who appeared just before he was thrown into the prison. Together, the two make a contract and return to the real world, where they are enlisted into the Pandora organization - a group researching both the Abyss and the trio that threw Oz into it. Along with members of Pandora, the duo searches to find Alice's lost memory fragments that are scattered throughout the world, to discover the secrets of the Abyss, and to determine if there's a way their contract can be broken without killing either Oz or Alice.
Faux-Victorian England, young aristocrats who just happen to be orphans, contracts with demons and supernatural entities popping up at all times, fancy dressing: it could either be Pandora Hearts or Makai Ouji. Apart from all this they combine a lot of parody with drama and rely heavily on a cast of very pretty males between which there are enough BL undertones to go around.
Pandora Hearts and Makai Ouji share a victorian feel, fantastical bishies and a similar mix of darkness and comedy. They just share the same tone - try out one if you liked the other.