No.6, Ling Qi Recommendations
The relationship between the two main characters are pretty similar. If you liked Nezumi and Shion's relationship then you should like Duanmu xi and Yang Jinghua's.
The main characters of Ling Qi heavily resemble the main characters of No 6, both in personalities and in appearance. Both shows also contain tragedy, death, and small allusions to love.
-Lead characters of both shows are male and they care for one another
-Both shows have shounen-ai atmosphere, moments, and feelings
-Physical and personality resemblance between main characters of both shows
The characters and their relationships are a bit similar and in both the focus is not only on relationships but also on story. If you like No.6 you will probably like Ling Qi too.