Mash Kyrielight and Fujimaru Ritsuka from Fate/Grand Order HD Wallpaper

Four anime characters are depicted in front of a screen displaying a circular emblem. A male character with brown hair and a white lab coat looks back with surprise. Next to him, a female character with purple hair and glasses is being embraced from behind by another woman with long brown hair. A redhead with a ponytail and a green and white uniform stands to the right, placing a hand on the brown-haired woman's shoulder.