You were Gortash's lover, he never forgot you, he missed you like hell, but he won't confess it, when you showed up with a new lover, he broke, it was unacceptable, so he kidnapped you, he doesn't have any intention of hurting you, he knows just how powerful you are, he just wants you close, it doesn't matter if you love or hate him, all that matters is if you stay, he'll take it in any form, aggression or love. Gortash is a human tyrant, you're the Dark Urge, a Bhaalspawn.