The Ancient Laws Explanation:

During the time before both the Titans of Mount Orthys and Gods of Mount Olympus existed, the age of the Protogenoi, an age filled with war and Khaos, an age where the wrath of the Protogenoi was unrestricted, an age where something as little as a petty insult could lead to battle across the cosmos. These wars between the protogenoi created a series of rules and regulations that would be forever known as The Ancient Laws... 

The Ancient Laws were created to limit the conflicts between the Protogenoi over the cosmos, as a way to bind them to their realms and avoid all-out war. This is why the first, only, and most important of the ancient laws created by the Protogenoi is that no immortal can enter another's domain without first being granted entry. This law ensured the Protogenoi could not cross between each other's realms to bring conflict. When the Protogenoi entered dormancy, this law fell upon their Titan and God descendants. 

When Kronos overthrew his father Ouranos, he became the protector of the Ancient laws To ensure the safety of his most prized artifact gifted to him by his mother Gaea, his jagged scythe. He declared that No Immortal could Steal Another's Symbol of power. This law made it so that only through mortal interference could a symbol of power be stolen.

After the fall of Mount Olympus and the rise of Olympus, it was Zeus who began to enforce the Ancient Laws. Still, it wouldn't be until the arrival of humanity that he would make any additions to the laws, the first of which is that for an immortal to be able to fight a demi-god, they must first be challenged. This ensured that Gods could not fully interfere in a demi-god's destiny. After the fall of Rome, Zeus decreed that Olympus would shut itself off to humanity, so he created the law limiting how much the Gods could interfere with mortal affairs. This law would ensure that Gods could not directly interfere in their dead children's lives. 

Overall, the effects and power of the Ancient Laws depend entirely on the one who created said laws; for example, the laws made by the Protogenoi are much stronger than those made by Zeus, as well as the power of the one who enforces them. This is why certain immortals like powerful Gods or Titans(And Protogenoi) can avoid punishment from some of the Laws, such as attacking a demi-god without being challenged or interfering with the mortal world. LWhereasaws such as No Immortal Can Enter Another's Domain Without First Being Granted Entry are enforced harshly due to the power of the protogenoi behind them.