Not sure if it was intentional, but Aislinn and Sisters work very well together!
My brother and I love to play Co-op and after a couple of duos with Aislinn that didn’t work out, we found wood elf Sisters of Twilight to be an amazing fit. The high elf factions help immensely protecting your forests while Aislinn and Sisters of Twilight port around the world securing high elf Colonies and healing wood elf Forests.
If you weren’t sure who to pair Aislinn with, I can’t recommend Sisters enough! We are having a blast this play through, we are fighting max strength Ultimate Crisis L/VH around the world on multiple fronts. It’s a challenge but a super fun and different way of playing than usual
Edit: I should have clarified I meant sisters of twilight in my post, apologies for any confusion if anyone thought Sisters of avelorn