Khal Drogo is introduced as a rough, unfriendly, and ruthless warrior king who was granted a reluctant young Daenery as a way for her brother to secure political power.
Emilia Clarke as Daenerys was terrified of Khal Drogo and he didn't do much to make her feel comfortable in the new place.
However, before the end of Season1 of Game of Thrones, both Daenerys and Khal Drogo fell in love with each other.
As the honeymoon period comes to a brutal end for the newlyweds then Drogo is minorly injured in a fight.
As Daenerys applied salve on the small cut of Khal Drogo but it becomes infected, and Khal Drogo falls seriously ill.
Desperate to heal him, Daenerys begs a woman which was recently taken as a slave to use her magic to save him.
The woman agrees but betrays her as the ritual performed by her results in the stillbirth of Daenerys and Drogo's baby and Drogo survives only in a catatonic state.
Daenerys realizing Drogo will never recover the heartbroken Daenerys kills him by smothering him with a pillow.
After a combined loss of Daenerys' much-anticipated child and the death of Drogo. Daenerys was left alone.