It's the first light sword which means he completed the maze and killed the boss there and go to next realm pleroma and kill the true god of caelestis that will cost you 1hour+ of fight to defeat and get that sword
You have to beat all of Caelestis and its bosses, after that head to the realm named “Atroxia Mortem” which is the 2nd blue portal on the left. Once you see the graveyards, go to the fourth last grave on the upper side and drop down.