so kang inha was not evil before but after discovering  that his father had no expectation for him but for tae oh as he really wanted to be praised by his father so he felt that inferiority complex and thought that i am from kang family and tae oh is nobody so how can he have my position and he also felt neglected by everyone so he wanted to be above everyone to prove that he is capable but his path was wrong as killed his brother kang inju and trap han taeoh for that to remove han taeoh from his path and to make tae oh on bad side of chairman kang jangmoo and then he literally killed and and tried to remove everyone who came in his path as he tried to kill chairman too and later he tried to kill mo gijun to as he was the only eye witness to his wrongdoings and so on and at the last when he went to prison for life sentence  taeoh gave him a photo of him , tae oh and na hyewon then kang inha realized that how wrong he has done and felt guily for ruining his own life and hanged himself in prison and died 

 ubahrubatuba:

You're not missing anything, I felt like that was a 180 as well with Kang Inha. Suddenly he goes totally bad after all these years? It was a major story hole and one that left me very disappointed in this drama.

They had all these great actors and this is what they do??!

Everyone is suffering from PTSD?

He was sentenced to life imprisonment and committed suicide.  He really missed their time at uni.  That was the time he was the happiest.

Money and power can never buy happiness.

 mparthur:

In Ha is mentally unstable.   I knew he would go astray from the moment he enrolled two assistants to join his team in his first negotation with the Daejong Enterprise.  

Tae Hoen smelled rat.

ı sensed that too but was tring to ignore it. ı told myself " this show can be diffrent dont lose hope. they can reach happy ending together"