Although the Heavenly Battlefield doesn't block Space Artifacts, no one has ever thought of using a Spatial Divine Artifact to bring people in. On one hand, Space Artifacts that can carry people basically don't exist. The Devil's Ring is called a Divine Artifact largely because it can carry living creatures, whereas other Space Artifacts can only carry things without vitality.
Ling Feng possessing the Devil's Ring was quite an unexpected event, and both parties entering the Heavenly Battlefield duel are strictly prohibited from using other cheating methods. If caught, the cheating side must unconditionally forfeit!
But this agreement doesn't affect Ling Feng at all. He doesn't care who wins or loses, and he has also found that outsiders cannot detect what's inside the Devil's Ring.
This is probably one of the features of the Devil's Ring as a Divine Artifact. Otherwise, when Ling Feng came out of the Qiankun Furnace, he should have been discovered already.
