Rean immediately noticed something different between the Deep Sea Monster Assault and the Life Syphon Forest. Both realm's formations allowed the attacking enemies to find anyone hiding with any kind of technique. However, the time of transferring the information to the enemies was different.
Because there were a lot of insects, demon beasts, and plants, it was too hard to warn all of them at the same time. There was then a slight delay in reacting to Rean's movement. By the time they attacked the position where Rean was a moment ago, he and his group had already used the battle formation to get out of there.
It only worked because of Rean's Light bending skill. Normally, the insects and demon beasts would 'see' the enemy and then attack. In that case, there wasn't a need to warn them as they could do that on their own. But since it was impossible to see Rean with one's sight, they had to rely on the realm's formation, which was too busy controlling everything.
