Ling Qi, Banana Fish Recommendations
The relationships between Ash Lynx and Eiji Okamura is similar to Ki Tanmoku (Duanmu Xi) and Keika You (Jinghua Yang). Ash Lynx and Ki Tanmoku are both leaders/influential people who have a strong, no nonsense persona. When Eiji Okamura and Keika You enter their lives, Ash Lynx and Ki Tanmoku find that they are letting their guard down and trusting the new person.
Side note: The plot of Banana Fish with fighting against "Papa" is more similar to Ling Qi 2 where the characters fight against an organization/powerful person.