It's pronounced: "EN-STACK." As for what it stands for, you'll have to wait.
We haven't seen him yet in the comic, but that's Arthur on the left. Is he what you imagined? Big bad Arthur...an older, overweight man who wears plaid? Well, appearances aren't everything. Some of the baddest people I know certainly don't look it.
And that would be a young Peter on the right, before he let the facial hair stuff really grow out. There's a whole crap-ton of answers coming your way in just a few pages. There's a bit more exposition than I would have liked, but hopefully it will be cool. And flashbacky.
Now is a perfect time to remind you wonderful readers about the Arc 5 Extension! The events of that very nicely compliment what's going on in Arc 9. The extension is an 11-page downloadable PDF available for $5. It's the events that happened between the end of arc 5 and the beginning of arc 6, narrated by Colbey, with one illustration per page! There are still some surprises in there. Click the banner for it in the sidebar at RIGHT to purchase. You can download it instantly after buying. Events of the extension are EXTRA, and not required to understand or appreciate the story.
Hope you all had a nice Valentine's day! Or Tuesday. That too.