The picture aids were very well done and provided a good visual cue to what was going on.
There was a lot of good information that I didn't know about... Anarius and Lilith, the creation of the world of Sanctuary etc...
But I just ... I couldn't keep listening to that man. I had to turn it off.
It's called pronunciation. I have to be able to understand what the hell you're saying. Use a clear tone of voice, and when using a lot of complicated or multi-syllable words slow down your pace a bit so the viewer has time to comprehend.
I found myself struggling a lot just to understand what you said. Plus, you're like ... eating your microphone or something and you're getting a LOT of plosives, which makes it even more difficult to understand than it already was.
Take a few moments and watch some news segments, a documentary or even a game-trailers game review. You don't have to do it the same way they do it, but you have to be clear and comprehensible like they are.
Over all, you're doing a good job though, and this is a great resource for a lot of Diablo fans like myself. Just next time when you re-do the audio track; listen to it yourself first.