A creature is blocking the landing on the shore. What can be done?

What kind of map is this? Now that the problem has already occurred, you'll have to cheat: a) use a cheat code to give a hero (even a secondary one) Flight and fly over the monster (first landing on the shore in another location); b) edit the save file, removing the monster from that cell. And in the future, when playing through author-made RPG maps, use the HD mod with the SOD_SP plugin, which prevents neutral creatures from appearing in unwanted locations.