Quote Originally Posted by Unregistered View Post
Your friends could use any eidolon from your teams that are in main slot. If you have 6 teams with 6 different element eidolons in main slots, they can use all of them. (Now the maximum amount is even 7 with phantom element)
To be more specific, the first of each element's Eidolon will be shown to your friends. So if you equip Diabolos in the main slot of team A, then only Diabolos will show in the Dark tab to your friends, even if you had Anubis in other teams. So don't do that.