Nightmare & Error's Kids:
Radier
Rewrite
Crash
Tenpatch
Midnight
Cyanid
Debug
Shade
Aylin
Mistake
Dusk
Infarared
Nightlight
Defect
Keron
Cresil
Mid
MidnightGlich
Vision
Lunoir
Aurora
Yin
Yang
Terror
Chaos
Void
System
Lunisolar
Raven
Reaper and Error's Kids:
Goth
Raven
Reno
Serif
Xeno
Gina
Gena
Sorell
Silver
Shino
Nomi
Rouge
Glitch
Grape
Bree
Mage
Autumn
Ari
Gwen
Shaza
Momo
Geha
Edom
Fade
Seikya
Half
Dean
Gloom
Mohagany
Massacre
Quietes
Mino
Azekiel
Thano's
Reaper & Nightmare & Error's kids:
Nyx:

Ps this picture is not mine give credit to the artist
Error actually gives birth to all of them she is the momma.
Children who were accidentally created by Errors and Ink magic combining well they are battling or Fighting: PaperJam & Gradient