Magic Synergy

Your D&D team has become skilled in magic and can strategize with your team’s available spells well. For each spellcaster in a D&D team, all of the spellcasters deal more spell damage in this sequence starting with 1 spellcaster (+0 damage) then 2 spellcasters (+1 damage), 3 spellcasters (+2 damage), 4 spellcasters (+4 damage) and so on. (0,1,2,4,7,9,10,11,13,14,16,20). All the spellcasters have to be 4th level spellcasters or higher and complete a campaign together (doesn’t have to be an official campaign) for this feat to work.