Typical Dark Teams

Here are the best element combos with dark I know of, roughly ordered by preference. In most cases variants exist.

4/5		⧉	good offense, sometimes used on moon gate
4/5		⧉	sometimes used on moon gate
3/5		⧉	sometimes used on moon gate
3/5		⧉	good against fire+light
3/5		⧉	also good against fire+light

All of those teams are only viable if you have two good totems. If you only have a good dark totem, better heal your team with Tidus. Maybe also replace Keros with Araji or Eden.