Can this card be used to bring out Oracle (2000 attack) and visionary (1900 attack)? Someone in a ranked duel did that to me and both of his recruiters were prismatic so I'm already suspicious of cheating.
If you had READ gravekeeper recruiter's effect properly AND also READ Oracle's DEFENSE stat properly, you'd know that it's possible.
Gravekeeper's Visionary is not in the game yet. You're probably thinking of gravekeeper's chief since you were mentioning 1900 attack. Both cases are possible since they have 1500 defense.