Board Thread:General Discussion/@comment-1031724-20161117051212

Comparing them by order of first to appear:

1.) Devimon and Nightmare Moon - Both associated with darkness, should have been more threatening but so early into the series somehow seemed less threatening than the others. Defeated for good at the end of their arc

2.) Etemon and Discord - Seemed less threatening as much as a comical villain who is kinda fun to have around. Is defeated at the end of their arc, but returns during the fourth villain's time (or season, in Discord's case) only to get their final defeat.

3.) Myotismon and Queen Chrysalis - Were more dark and sinister than the first two. Were thought to be defeated for good at the end of their arc, but returned way later on. The difference is, Myotismon was destroyed for good while Chrysalis is still out there, hopefully to change in the Season 7 premier.

4.) Piedmon and King Sombra - Are even more dark than the one that came before given Piedmon and the other Dark Masters destroying most of the Digital World and causing many deaths, and Sombra's enslaving the Crystal Empire. Both were also a threat in the past, and are destroyed at the end of their arc. (Sombra can also be compared to Machinedramon for having less screentime)

5.) Apocalymon and Lord Tirek - The biggest threat the heroes ever have to face. (Literally and figuratively) Both were sealed away in the past but returned, and took away all the heroes' power, until they either got it back or gained new power and defeated them for good. 