Voilà c´qu´y disent sur le forum du site officiel:
The " Pyramid Rune" can be found on top of a pyramid that you must climb. The pyramid can be accessed by jumping across the water pits with the flaming jets shooting across. A Shadow Demon teleports around on platforms that jut out from the walls of the room the pyramid is in. He´s a pain in the ***. Kill him with magic before you climb up or he´ll keep knocking you off.
The " Athena Rune", which is found across the swirling pit with the two moving islands and the Athena Blockers followed by running around the islands looking for chests to get crystals to activate more Athenas, which eventually takes you to a room that has the rune in it.
The " Knight Rune" which is a bit more complicated to get. It is found by first jumping across the 4 moving platforms without touching the water and entering the Shadow Gate on the far side. Once through that portal, you must play a game of Chess with Athena Statues to get to the Purple Shadow Sword. Once you get the Purple Shadow Sword you go to the room with the Knight in it and kill the Shadow Wraiths. The Knight will then have you place the sword in his statue in the big portal room. Then he will lead you through a series of portals which will ultimately allow you to land on top of the raised dais in the big portal room where the rune is actually located.
The " Soldier Rune"is really easy to get to. You jump across the first rune pillars and go through the shadow portal that doesn´t lead to the knight Room. Once in that hallway, you look on the walls and you will see pictures of a Minotaur and a Soldier. Go through whichever portal the Soldier is nearest to and eventually you will get to the last rune.
J´suis pas trop doué en anglais, mais j´crois qu´la rune d´athena on aurait peut-etre dû la faire en premiere, quand on avait plusieurs shadow stones de côté...J´ai pas de sauvegarde de secours, donc je sais pas si recommencer le donjon servira a quelque chose...Si tu le recommences essaie peu-etre comme ca...