Oberon
Robin (Puck)
Oberon
Robin
The word "anoint" derives from the Latin verb inunctum, to smear something on the body for cleansing or medicinal purposes. In ancient times people cleansed themselves by smearing olive oil on their bodies and scraping it off. (Inuctum also gave us the word "ointment," a healing cream or balm.)
One of the principal Catholic ceremonies is called Anointing of the Sick, during which a priest pours holy oil on a sick person’s head to elicit God's healing power. Similarly, Robin is going to pour Cupid's magic potion on Demetrius’ eyes to elicit passion.
Eventually the word "anoint" came to refer to any kind of religious blessing, but today we mostly use anoint in a figurative sense to describe someone who’s chosen, as if by God, for some office or position, as in "She was anointed by the Democratic bigwigs as their party’s presidential candidate."