add $fillable

app/Models/NissayaEnding.php

@@ -11,4 +11,6 @@ class NissayaEnding extends Model
     protected $casts = [
         'id' => 'string'
     ];
+	protected $fillable = ['id','ending','lang','relation'];
+
 }

app/Models/Relation.php

@@ -12,5 +12,6 @@ class Relation extends Model
     protected $casts = [
         'id' => 'string'
     ];
+	protected $fillable = ['id','name','case','to'];
 
 }