These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Busou Renkin
Alas, Poor Villain: Washio, the eagle homunculus. Don't worry, he came back.
Kazuki: You know, once you get better, we should all hang out sometime. We're your friends now. You don't have to be alone anymore. We're here for you.
Tears of happiness from Ouka follow.
Tokiko using Bravo's Silver Skin to rescue Kazuki, adrift in space, and reunite with him.
If you die, I'll die too... No. I want to stay alive, next to you. We'll never be apart again. [they touch their hands] Now and then... You and I... are one.
Ho Yay: The Furo Scene described in the Foe Yay entry. Actually, size comparison seems to be a recurring sub-theme in the series: in episode 18, we see Kazuki and Gouta taking a leak in a river, side by side. Gouta turns to take a peer at Kazuki and immediately thinks that, compared to him, he's an "UNDERDOG!!!" (complete with English text!)
Les Yay: Mahiro seems to like girls, especially Tokiko.
Narm: Could anyone take the fight between Papillion and Dr. Butterfly in episode 13 seriously due to their flamboyant dress and attack names?
Yes. And that's the most disturbing part...
Tear Jerker: Tokiko screaming for Kazuki towards the end of episode 24.