Ring | Frieren: Beyond Journey's End | Mirrored Lotus

 Frieren: Beyond Journey's End
The demon king has been defeated, and the victorious hero party returns home before disbanding. The four—mage Frieren, hero Himmel, priest Heiter, and warrior Eisen—reminisce about their decade-long journey as the moment to bid each other farewell arrives. But the passing of time is different for elves, thus Frieren witnesses her companions slowly pass away one by one.

Before his death, Heiter manages to foist a young human apprentice called Fern onto Frieren. Driven by the elf's passion for collecting a myriad of magic spells, the pair embarks on a seemingly aimless journey, revisiting the places that the heroes of yore had visited. Along their travels, Frieren slowly confronts her regrets of missed opportunities to form deeper bonds with her now-deceased comrades. (From Frieren Wiki)

Frieren is a petite, female elf with green eyes, thick eyebrows, and long, white hair parted in the middle and tied into two high pigtails. Like all elves, she has large, pointed ears. ... She also wears black tights, brown boots, and a pair of gold earrings with red, teardrop-shaped jewels hanging from each earring. When casting spells as a mage, she utilizes a red staff with a gold, crescent-shaped tip that holds a red jewel in its center. Her staff has gold accents and a red ribbon tied at the tip.

Himmel loved Frieren greatly, going so far as to give her a mirrored-lotus ring symbolizing eternal love. He understood the difference in emotional and time perception between a long-lived species and himself, and knew that Frieren would not be aware of the meaning behind his actions. 

(From Frieren Wiki)