Kelly Schade-Burkhardt

Kelly Schade-Burkhardt is the son of Nick Burkhardt and Adalind Schade. He is the younger half-brother of Diana Schade-Renard. He was conceived when Adalind used the potion to disguise herself as Juliette to take away Nick's Grimm powers after they slept together. Adalind didn't know she was pregnant until Henrietta sensed it and let her know. Soon after breaking the news to Nick that she was pregnant with his child, she revealed she was having a boy. Kelly was named after Nick's mom and he was born via an emergency C-section due to his arm being above his head when Adalind was trying to give birth.

Trivia

 * He was named after his paternal grandmother, Kelly Burkhardt.
 * Kelly is the only child (that we know of) to have a parent who's a Grimm and the other a Wesen (in this case, a Hexenbiest).