"Wow, okay, let me back up. You are from outside Pharasma's Creation, after all." He makes an exasperated gasping noise.
"It's best if you ignore how your world's afterlife works, since, now that you're here in Golarion, your soul is probably under Her jurisdiction now, so long as you remain here. When you die, Pharasma holds a soul trial for you, where it is decided, based on your actions and thoughts in life, which afterlife you are deserving to go to. There are nine. Going from Lawful to Chaotic, we have Heaven, Nirvana, and Elysium for Good; Axis, the Boneyard, the Maelstrom for Neutral; and Hell, Abaddon, and the Abyss for Evil.
After your soul is so assigned, it becomes an 'outsider' by the process of internalizing the ethics and energies of the place: outsiders are not human and are immortal, and also always express the alignment of their afterlife plane. They're much less malleable and changeable than mortals.
The Good afterlives are generally good, but the Evil afterlives are awful. In Hell, you are tortured for eternity by Asmodeus and His devils, in Abaddon your soul is eaten by daemons, and in the Abyss, you fight with other demons and probably die. Generally not a good time. I'd rather wander Elysium and its infinite wildernesses.
This creates an awful dilemma, see: what if I want to be Evil and do cool fun Evil things while alive, but also don't want to die the true death in my afterlife or get tortured forever and ever? That's where Conrad and Damian come in. They have a very nice and pleasant Abyssal realm, unlike the general awfulness of the Abyss. I can show you if I ask Rendon to Scry.
Now, ordained people – people who are chosen specifically by gods because They want them to advance their interests in the Material Plane, and because their soul is of a very pleasing shape to Them – are already destined to go to their gods' respective afterlives when they die. But for those who are useful but somewhat less pleasingly shaped, there are soul contracts, which is like being-ordained-lite – it permits you to go to Their afterlife in exchange for your mortal service.
By 'pleasingly shaped', I mean that your values and thoughts are particularly aligned and agreeing with Theirs. For Damian, He is the god of exploring and experiencing the wide range of positive experiences available to you, so he selects people who are indulgent and discerning and honest about their desires.
Following Him means that I get to have a pleasant afterlife while still getting to do everything I want to do here in this life. I do so love escaping the consequences of my actions. Don't you?"