The Fenrir Team was both the first and last NPC partners Double Leaf had when she started playing "The Realm of Innocence." Admittedly, her social circle now isn't small, but strictly speaking, her mentor Ana Ta Lasha's role is more like an elder, the kind you can behave casually with; whereas Diana is a slightly absent-minded scholarly big sister, who in daily life actually needs Double Leaf, the 'apprentice,' to take care of her.
As for the others, there's no need to mention them. Diana's brother, the Mist Moon Sage Kenneth A. Achizolti, is a sponsor, investor, and supporter, while the Prince Regent Xiu Bresen of the Violet Empire is a collaborator who shares the same goals at certain times.
In short, none of them can really be counted as partners.
