Achilles’ heel  The one vulnerable spot, a sole weakness. (Achilles could be wounded only on one heel.)
mad as Ajax (Because he stabbed himself in a jealous fury when Hector’s armour was awarded to Ulysses.) [See Shaks, LLL IV.iii-1595]
Althaea’s brand A dark force which will ultimately take effect. (She believed her baby son would die when the brand on the fire was burnt away, so she snatched it from the fire and locked it away. But in a later act of revenge she threw it back on the fire.)
Amazon Masculine, strong, dominant, formid-able woman. (The Amazons were warriorwomen of fabulous Scythian race.)
apple of discord Cause of dissension. (From the golden apple contended for by Hera, Athene and Aphrodite as the prize for beauty)
the golden ball rolls to everyone’s feet once in a lifetime [Oxf]/the golden ball never turns up but once Everyone gets their big chance, their stroke of luck, sometime in their lives.