Some yaois like killing stalker + Warehouse include
http://www.mangago.me/read-manga/nishikaidan_no_akuma/
http://www.mangago.me/read-manga/prisoner_kaen/
(● ̄(エ) ̄●)
I don't know of any other webtoons to suggest about kidnapping but here's some yaoi/shounen-ai you might like, they're all kinda dark and somewhat psychological
Shounen-ai:
http://www.mangago.me/read-manga/let_dai/
http://www.mangago.me/read-manga/acid_town/
http://www.mangago.me/read-manga/zankoku_na_kami_ga_shihai_suru/
Yaoi (Sorry, these aren't lengthy):
Most of Harada's manga
http://www.mangago.me/read-manga/kokoro_o_korosu_houhou/
http://www.mangago.me/read-manga/the_inheritance_of_aroma/
http://www.mangago.me/read-manga/j_no_subete/
http://www.mangago.me/read-manga/coponicus_no_kokyuu/
http://www.mangago.me/read-manga/itou_san_kuraka_sui/
http://www.mangago.me/read-manga/sakura_gari/
Hi guys! I'm looking for manwhas.
For shoujo, I want something like Lan Chi
For shounen-ai/yaoi, I want something like Killing Stalking, Warehouse, Bastard and such
I also prefer manhwas witha a generous amount of chapters with generous amount of pages per chapter. Whether ongoing or complete, full colored or not, it's fine. But you can just actually suggest anything. Thanks in advance
ε=ε=(ノ≧∇≦)ノ