Is Merlin and Waver worth putting on the same team or just one of them is enough? If both of them, who would be the third servant? If only one of them, which one and who would be the other two servants?
double waver is mostly used for daily, farming quests.
Merlin waver is used for hard quest and survival quests.
3rd servant should be a buster hitter and has own critical star absorption and np regeneration like drake
One of them is enough if u like challenging