Now, who is Melenis?
Meandor’s favorite wife, as vota dc days. Important part, she was also a high ranking commander of the Cult of Storms, which was the Dark Elf faction in 1, and supported the eradication of all humans. Broken at the end of AoW 1 storyline, this organization has vanished. During AoW 2 SM, we see Meandor, the big leader of the Cult, support his sister Julia, who beat him in AoW 1.
Why does she want to destroy the world?
Not really known – though there’s some hints in the end briefing – my first playthrough I allied with her as well. Basically, she prefers death above life and wishes to spread the peace of death upon all.
Why Ham Binger and Sundren turned against me when I stood against Werlac?
because Werlac doesn’t want to control the world, only to let the Wizard Kings of old return. While Sundren and Ham Binger don’t want this, it’s still highly preferable above the death of everyone and everything.
Wouldn’t world still be destroyed if seals would be broken?
No – however, it would once again be possible to travel in and out of the shadow world. The last time that was possible, the population of Athla(the current world) was almost wiped out by the Shadow Demons. They beat them in the end, but there’s no desire to do so again.