Constanqueen

Constarrow is the slash ship between Oliver Queen and John Constantine from Arrow.

Canon
2010

While secretly stationed as a spy on Amanda Waller's orders at Lian Yu, a returning Oliver learns that his camp is looking for something other than slave labour for their drug trade. Their leader is searching for something mystical and when Oliver's sent on one of the search missions, he happens upon Constantine, who takes him hostage and brings him into the 'cave of wonders' where the mystical artefact is located.

Fandom
AO3