Herakles (also spelled "Hercules") is a noun from classical mythology. It refers to a famous hero known for his incredible strength and bravery. In stories, he is most well-known for completing what are called the "Twelve Labors," which were a series of very difficult tasks he had to do to earn immortality (to live forever).
While there aren't specific idioms or phrasal verbs that use "Herakles," you might encounter expressions like "Herculean task," which refers to a job or task that is extremely difficult and requires great strength or effort, much like the labors of Herakles.
Herakles is a legendary hero from mythology known for his strength and the difficult tasks he completed.