1: How effective is sunglight against the Undead? If even the slightest amount touches them do they explode into flames, or is it slower?
2: Is it possible for an Undead creature to maintain its personality and continue to act human, or does the undead go feral as soon as its created?
1: It's not instant, but it's pretty fast. If the sun touches them, they start to sizzle and smoke, and pretty soon WHOOSH! Some vampires walk in sunlight by covering themselves from head to toe, including a veil or mask over their entire face, but even this will not work if they are exposed to bright sun for extended periods. They also find it rather blinding and dizzying.
2: Depends on the type of undead. Obviously, vampires and liches retain their personality and continue to act human. Lesser undead often have no soul at all - just a demonic mockery of one - and thus are incapable of human thought.
But I assume you are asking about those lesser undead created with a mortal's soul trapped in a soulstone. In the majority of cases, the soul inhabiting the undead creature goes mad from the torment of its existence, as it is forced to watch its new undead form carry out the necromancer's commands. BUT in very rare situations, a soul of unusually strong willpower (usually that of a mage or shaman) can maintain a grip on itself and even gain control of its new undead form. This usually happens after the necromancer who created it has already died, but in some cases they may even be able to break the necromancer's will and turn on him.
Come on guys, no one is playing Monster Hunter World??
Holy crap, ZERO! Long time no see.
Yeah, that's one I've been looking at. I've never played a Monster Hunter game in my life, but I enjoyed the heck out of Dragon's Dogma for a while, and since Monster Hunter World is a similar game on the same engine, I thought I'd give it a look... until I got to the part of the video where the guy pulled out the Gatling gun, and a girl with goggles on her head started bouncing around, and there was a little talking cat-person... Then I thought "this might be 2anime4me" and bailed. Might give it a try eventually, but I'd really prefer a Dragon's Dogma 2. :[