I've seen art of this ship a few times now; have they been flirting with each other?
Perhaps: https://youtu.be/ADHOAyET4Oc
35:36 but the whole vid is a date anyway. HoloEN is the yuri generation...unless in the future EN gen 2 has married couples or something.
Exusiai is the cheerful and joyful best friend that is willing to kill another person if they threaten Texas, a subtle yandere, while Lappland is yandere that is actually very sad, a way more direct yandere.