If you're looking for anime similar to Ballad x Opera, you might like these titles.
Tsuzuki Asato is a shinigami: a guardian of death. Acting as an investigator in Juuouchou, the bureau in charge of ensuring that each soul passes through the cycle of life naturally, his job often involves dealing with those who would disrupt this cycle. His life after death is about to change, however, as he is assigned a new partner, Kurosaki Hisoka, for a case in Nagasaki - a case seeming to involve some sort of vampire. But the two shinigami soon find that something deeper lies behind this blood-sucking menace...
One night, two mysterious figures infiltrate the Twelfth Squad’s laboratory for nefarious purposes, wiping out a third of Seireitei in the process. Amidst the commotion, the intruders approach Rukia and indirectly cause everyone she knows to forget about her – that is, except for Ichigo, who manages to escape this mind alteration. Sensing that something is wrong, Ichigo travels to Soul Society for answers; but with obliterated memories, everyone treats him as an enemy. Now, with all thirteen protection squads chasing him, can Ichigo find a way to retrieve the lost memories of his friends and rescue Rukia - not to mention find out why was she targeted in the first place?
The peace is suddenly broken when warning sirens blare through the Soul Society. Residents there are disappearing without a trace and nobody knows who's behind it. Meanwhile, a dark shadow is also extending itself toward Ichigo and his friends in Karakura Town…
The anime's story is set in both a celestial realm of angels and demons, as well as Nippon Cultural Broadcasting in the mortal realm. The angels, who use the power of love to protect the peace of the Earth, have their sight set on the "Love Nights!" radio program, so they send rookie angels to Nippon Cultural Broadcasting, and end up fighting the demons that face them. Morikubo, Yoshino, Fukuyama, and Suwabe play the angels and demons in conflict, while Yonaga plays the goddess in the celestial realm who stands neutral in the conflict.
A young woman quietly falls to the earth, escorted by a solitary crow. This sort of dream, as many other before have dreamed, comes just before being reborn as a Haibane, a charcoal-winged angel. On the outskirts of the walled-in city lies Old Home, a haven for Haibane to study, live, and learn, while waiting for their chance to ascend to the heavens and escape the confines of their new world. Rakka is the newest inhabitant of Old Home who wants nothing more than to remember her past and discover the secrets of her kind. Together with Reki, Kuu and plenty of other new friends, Rakka will laugh, explore, and search for the meaning of their existence in the process.
Tragedy struck Kotaro Higuchi as a child in the form of his mother's death in a car accident. But fate has a funny way of doing things, and years after the fact an angel-in-training named Misha decides to pay him a visit. Joined by his fellow elementary school students, and later by the nicest demon you'll ever meet, Kotaro and Misha will embark on a journey of laughs and love.
Momo is a sympathetic death god who cries every time she sees a touching moment. Though she brings death, she also allows the victim to complete their last wish before taking them away. Accompanying her through her adventures is a winged black cat named Daniel. With a huge scythe in tow, Momo strives to touch the lives of humankind and overflow the world with pure kindness, by fulfilling the soon deceased’s tasks.