Preview
Curious on strange lights at the abandoned factory behind the school, Kazuki ends up witnessing a monster attacking a seemingly defenseless girl. Trying to save her, he ends up dead as the monster pierces his heart. The girl, however, is an Alchemic Warrior named Tokiko, and feeling guilty for Kazuki's death, gives a Kakugane (An alchemic unit of great power, which can be used as a weapon or a Busou Renkin) replacing Kazuki's heart. Now, he is also an Alchemic Warrior, one who have to fight against the fearsome Homunculus, creatures controlled by evil Alchemic powers which grant them eternal life, but the need to eat humans.
Pacing
A fair warning to any action fan, Busou Renkin is not about the lame “monster versus warrior” overdone plot, nor the fighting sequences, but about it's characters, most importantly the romance that emerges between Kazuki and Tokiko.
Most characters are interesting enough to hold you after some cheesy starting episodes, and some villains steal the shine with a lot of parody on the genre, like how people make fun of the ridiculous clothing they wear or the situations they are in. If you ever felt weird that nobody told how gay or lame a particular hero/villain clothing was, you can bet Busou Renkin will point that out and make fun of it. Characters also behave in a particularly interesting way, with Kazuki's sister and friends being memorable in their secondary roles as really mature friends who can adapt to change. In the end, Busou Renkin is not about the fights or the "save the world" rethoric, but about how a warrior girl cope with love, and an utopist boy wishing to save everyone has to grow up and make compromises.
Conclusion
The title has two arches, the first being the "mission" where Tokiko currently is as the anime starts, and later a much bigger danger befalling mankind, involving all Alchemic Warriors. However, most of the time, Busou Renkin devotes most of its screen time for character development on both Kazuki (who slowly learns the ways of a warrior and how to handle his new powers) and Tokiko (who falls in love for Kazuki and learns about friendship). Unfortunately the main plot is weak and unentertaining most of the time, but if you do not raise much hopes on it, and just focus on the characters, even the secondary ones, you will probably greatly enjoy this particular series.
Another interesting note about Busou Renkin is that most characters are not really stereotyped dichotomic entities of plain good and evil, and Kazuki's personality will help twist their will into a more gray zone of fact versus need, instead of good and evil: some "evil" characters get real and leave their egoistical goals, and some "good" characters release their wrath in the wrong place, with unexpected changes and twists, always on character development and not plot, bringing a good shine to this otherwise weak show. If you can get past the cliché and predictable plot, you will be pleased with good and strong characters, where the lead female is not your hot beauty-beyond-all-reason babe nor is the male lead the best fighter history has seen - and yet, when Tokiko smiles, you have no other choice to concede her beauty the same way as you have to accept that Kazuki's heart and will is a lot more important then his skills - or so the director wants you to think that way. It works, if you want.
