If you're looking for anime similar to Loveless, you might like these titles. All recommendations are made by Anime-Planet users like you!
The Holy Grail War is a battle between seven magicians who each summon a mythical hero to fight for their cause. Shirou, a twice orphaned high school boy, had so little magical talent that his foster father did not bother teaching him about the war and its meaning. Thanks to that lack of foresight, Shirou finds himself in a bit of a pinch when he accidentally summons a hero of the strongest class, and is sucked into the fray. The Grail grants the winner any wish they have. But driven by an unyielding sense of justice and self-sacrifice, for what will Shirou fight?
In both shows, an unsuspecting boy is thrown into a bizarre world of fighting due to the lifestyle of a dead relative. Both of these shows involve groups of fighting pairs who have a master/servant relationship, with the fighter exerting the effort while being subserviant to a master who can aid in battle by increasing the fighter's strength and giving orders. In both cases, the pair is bound together by some deep destiny and their bond allows them to connect with each other on a more spiritual level. The fighting is similar too, involving magic and complicated relationships with people who are supposed to be enemies. The two shows are dark and bittersweet and overall have many similarities.
Chisato Takatsukasa would like to think he's a normal concerned parent. His attractive son, Riju, has many male friends and Chisato is certain that they all want nothing more than to take advantage of him - and thus he concocts schemes to scare away each and every one of them. However, there's one man who doesn't seem to get the hint: Shunsuke Sakaki, Riju's best friend who is secretly in love with Chisato. Through a series of encounters Chisato comes to realize he has feelings for Shunsuke as well, but what about Riju and his feelings?
Like shounen-ai? Of course you do, otherwise you wouldn't be reading this recommendation. In my experience, most shounen-ai is pretty similar (everyone falls nicely into the seme vs. uke dichotomy, etc.) so if you like one (Kirepapa, for instance), you'll also like another (such as Loveless)
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.
Pandora Hearts is a shounen whereas Loveless is shounen-ai, but if you like the idea of two people teaming up to fight magical/supernatural battles (where one of the characters is a tsundere), with a plot that's heavy with mystery of one, you're bound to like the other.
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.
Both of these anime have young boys who make older men do their bidding, and in most cases fight battles for them. The older men would "do anything" for their "master" for various reasons.
If you like children who have the dominant hand in an adult-child relationship then I can definitely see someone liking both of these.
Upon trying to save a friend from bullies, Shibuya Yuuri finds his head in the unlikeliest of places -- the toilet. Like a flash, Yuuri is then inadvertently sucked in, transporting him somewhere else! In this unfamiliar world of flying skeletons and magic, he is informed by a group called the Mazoku that he is to be the next Maou -- ruler of the kingdom! With harrowing and embarassing situations ahead, can our hero swallow his pride and lead a war against the common people when he can't even tell the difference between a slap in the face and a marriage proposal?
Both animes have something to do with fighting, but that's not the only reason why they are similair. They both have some shounen-ai hints. Yuuri and Wolfram (KKM) are engaged and they sleep in the same bed, but you never acutally see anything. Loveless has a lot of sexual hints, like how children lose their ears if they have sex. Soubi says he loves Ritsuka constantly, but nothing really happens, even thoug it's clear they have chemistry together. If you liked KKM and don't know loveless yet, you do have to keep in mind that Soubi is a great deal older than Ritsuka.