Dragon Quest V/Headscratchers

Literacy
Main Character can't read as a child. He then spends the next decade as a slave building an evil temple, and, when we see him next, he knows how to read. Why, exactly, did the evil cult teach their low-level packmule slaves how to read?
 * I figured that Henry handled it. Scratching letters in the sand, and all that. Not like there was much else he could do to thank him at that point, until the Time Skip ended...
 * Evil cult outreach program at the local university. Looks great on a resume.
 * Henry took your father's death very hard, since he was partially responsible for it. It's not a longshot that he taught you to read in an attempt to compensate for his previous spoiled brat personality.

Zenithian Sword
Okay then, let me get this straight. Both Pankraz and the Hero cannot wield the sword because it's implied to be too heavy for them. Yet, why is it that the Hero's 8 year old son can carry it with no problem? Looking at the official art, both Pankraz and the Hero look strong enough to carry almost anything. Sooooo.... Is the son only able to carry the sword because of the lineage from his mother's side, or is it that the Zenithian sword doesn't like to be carried by older people?
 * Because the son is the Chosen Hero. He can lift it because he's The Chosen One, and his father and grandfather can't because they aren't. Simple as that.
 * Partially justified by the fact that neither are Zenithian. The sword itself seems to have a lock-out measure that refuses to let itself be "wielded" by non-Zenithians (they can still carry it, just not use it). The Zenithian helmet has been stated to shrink when he put it on, so one could suppose that if that shrinks to suit him well, the rest of the armor and the sword does so as well. As for why his sister can't use it, well, she's justified in-game as to being literally not strong enough to. Curiously, all of her other stats besides strength actually SURPASS her brother's, so that may explain why she can't equip the armor (she doesn't need to).  If that's not justification, only one more thing could be, and that's a given.
 * As the above long post says, there's a feature that locks anyone but The Chosen One out. Specifically (in the DS version, at least) when you first find it and pick it up, the game says that you can feel the strength being sapped from the hand that's holding it and that your body feels like lead. The sword itself isn't actually all that heavy -- it just weakens anyone unworthy of wielding it.

Debora
Her over-the-top It's All About Me attitude can be amusing, but there's one detail that keeps bugging me: how she keeps referring to the hero as her slave rather than her husband. Mainly because, well... he was actually a slave for ten years. You'd think that having his own wife refer to him so casually as her slave wouldn't go over so well because of that, and that he'd explain this to her. The Heroic Mime argument doesn't work, since a certain scene spells out that he does speak normally; it's just that we don't normally get to see what he says. And it's not like he kept it a secret, because a few late-game Party Chats with Madchen reveal she knows he was made a slave for ten years. So if his young daughter knows about it, why wouldn't his wife? And if Debora knows about it, why would she keep calling him that?
 * Because Debora is all about the dominating - as long as she's on top, in control, getting her way, and being treated like a princess, she doesn't really care what others think about what she says or does.
 * One can assume that, if the hero actually chose her, he loves her despite this. It's not like she isn't completely upfront about what their relationship will be like. Maybe all that time working for Zugzwang gave the hero a submission fetish? Provided it's performed by busty girls, anyway.
 * Just her chest? You aren't giving Debora enough credit. Cinematics have been made to show just how "Bon kyu Bon" she is (roughly translated: "Va Va Voom").
 * In the original Japanese, Debora calls the main character her "geboku," which is a bit more accurately translated as "manservant," than slave.

Treacle
When Treacle asks the hero as a kid to come close and let her get a good look at him after he brings her the Herald of Spring, why does he back up half-way across the room from where he was standing next to her? Is she far-sighted or something?