Thread: [Event 18] Advent Battle vs Vritra

The bonus is about +0.4% to overall damage per eidolon, for a total maximum bonus of +2.4% (assuming all 6 eidolons match all 5 party members). The bonus is insignificant compared to other factors, which is why I don't even mention it in my guide. Mention of it just leads to confusion.

It's a good idea to collect same-element eidolons, however, since in about 8 months there will be eidolons whose passive bonus is dependent on the number of same-element eidolons equipped (up to a max of +50% elemental damage). With the right configuration, that makes them the best event eidolons (for equipping as primary) to date in the DMM version.