There is a world which is full of monsters and everything they hear is inverted (i.e. If you say "Moob" they will hear "Boom")
There is a Treasure Chest and it is Locked. In order to unlock you need to kill the Monster nicknamed "SAP" with his sons the 5 Dark Elves Archers every Dark Elves is Carrying "SAP" name (1 Letter each Dark Elves).
In order to defeat "SAP" he must hear his Name
If you kill the Dark Elves Archers you will receive a "SWORD"
What is the Monster Name?