Fjord and Caduceus are the only members of the party that aren’t mostly humanoid—and members of the Orc and Giantkin species have basically pon farr/fantasy pms cycles. And Caduceus is the first other person Fjord has met that also goes through them.
Fjord/Caduceus, Synced Rut Cycles
Xeno!Smut and emotional bonding ensues.