Former ruler of Hell he had tricked his assistant (Asmodeus) into taking over for him “For a little while.”The ruler of Hell was granted almost divine power, but with it came the problem that one could never leave their post. So he simply learned to redirect the power until he found a worthy advocate for his job,One who could trult handle the authority and power of Hell itself. He began by limiting his exposure and transferring his duties to Asmodeus while still staying in the nine planes,but most importantly being able to leave the ninth plane which he was connected to. Finally came the time (days don’t have any meaning in Hell, Duh!) when he claimed to have business with the Abyss,
:One of the nightmares in ruling Hell eas the problem that devils havee a job torturing souls for redemption in Hell, demons on the other hand are agents of chaos and corruption who live in the Abyss an entirely different plane of existence. Some poor sucker would say the words :I send thee foul creature back to Hell." Well he did go to Hell but he wasn’t from there, and usually destroyed the planned tormenting so had to be found get his name(Hard to do) and send him home to the Abyss.Meanwhile on the mortal realm some other poor sop says “I summon thee demon from Hell!” and all of the devils hard work goes to no avail and now they have to go back to their job and also be on the lookout in case he comes back or his brethren, sometimes paperwork can be Hell, but I digress.
After tranferring his abilities to Asmodeus he did go to the Abyss(Lawful Evil remember?)
after the usual threatening and rhetoric got through they signed over and retrieved each others people and sent them to their respective homes. In his weakened state he was able to be summoned ny mistake to the mortal realms.(It was planned and orchestrated) including the magics to hide him not wanting to return, let Asmodeus bask in the Hellish light. He has been hiding from Hellish minions ever since. Asmodeus has learned to enjoy his job and authority but despite being tricked into it, is more worried that Galon might try to take it back.