Markus and others thoroughly searched the danger zone but until now they did not find any kind of suspicious movement in the danger zone. Naturally, there is also a possibility those survivors have some kind of techniques to hide from the observation technique of those Saints.
This is a possibility because previously those people used this kind of technique to hide themselves. Well, those people should have more powerful hiding techniques. Because of this, the saints were unable to find any kind of clue about them.
But that does not mean the Saints will give up. They are still searching in the danger zone. Even if those people try to hide themselves, they naturally will leave some kind of trace and all the Saints are currently looking for that kind of trace.
On the other hand people present in the battle area also observe the core still present in the mid-air. The core evolves while the surrounding spiritual energy also evolves.