Prologue:

A young Garmadon trains with a girl that looks just like him. After a bit, his father comes out to inform that he'll be getting a little brother soon. The girl hugs Garmadon. "WE'RE GONNA BE A BIG SISTER AND BROTHER!" She calls. The father laughs. "Calm down now Gardenia." He says to his daughter. She nods and calms a bit. Garmadon looks to his twin and challenges her to a race.

When the child is born and named Wu, it was discovered that he came with three other siblings. A girl and two more boys. In birth order it the total of children were: Garmadon, Gardenia, Willow, William, West, and Wu.

An hour later, Gardenia is called to talk with her father. He tells her of her engagement with a young lad named Ryan. She would be wed to him for the sake of both families. At this she got angry, not wanting to marry anyone. Ever. She was then sent to her room, when she told her twin, he helped her run away. Willow was sent to Ryan's family, she'd be raised to marry him, and William and West were kidnapped. This left Garmadon and Wu to grow up together and alone. Wu was never told of his other siblings, Garmadon being left to know the sole truth.

Years latter, Garmadon discovered that Willow ended up leaving Ryan and was now married to Clouse, but she had no clue that Garmadon was her elder brother. Next he found William married to a demon and West married to an angle... both woman were obviously from a different realm.

He latter found his dearly beloved twin, who was in love with an Anacondrai. He helped the two marry in secret.

Years latter.....

All betrothed siblings were found dead.... Willow died in war and Clouse never knew he had a son with her, Garmadon happily took the child in. William & West both died in an attack along with their wives, both son's were taken in by Garmadon. Gardenia died not long after escaping death, saving her daughter in the process. Garmadon took his niece in happily. 

He never even told Misako, having promised his father to not tell anyone of his other siblings...

When he got banished to the underworld his taken in children where brought there by the skullkin. They remain a secret to this day.

But will one break the number one rule?