But have you read PC's workshops? They're very useful in developing characters and all, you know.

Have a link to his one on characters! I'd recommend read the rest of them, too. Fascinating stuff, it is. Useful, too.

And good luck with your next attempt!

No. Just… no.

This character doesn't work in many ways. Desdendelle has already touched on several major points (what is a Diplomancer, uninteresting personality, major errors in PPC canon), so I will specifically look at Terraria canon issues.

The big one is that Terraria itself… doesn't really have a story. Or a unified world, really. The only true canon to Terraria is detail-based: what the monsters are like, what the NPCs are like, and so on. Much like Minecraft, the only story is 'kill the bosses.' This character might as well not be from Terraria.

Are you trying to claim that the NPCs are the 'inhabitants?' Because that is a stretch I cannot buy. And how can Terraria get the Internet if they don't even have computers? Their most advanced technology is wires hooked up to pumps and sensors.

But let's put that aside. Let's say that Terraria has a fully fleshed-out world. You've given knowledge of the PPC to an entire universe! That's bad both in-universe (the PPC's trying to be secret here) and out (it suggests that you don't quite get what we as a group are about).

You want my opinion? Scrap this character. Begin from the ground up. Make multiple characters as thought exercises. Like Des said, that might help you see what makes a character interesting.

-PPC knowledge is lacking. DoSAT has no RCs and its technicians usually don't go on missions.
-What is a Diplomancer and why is Trevor one?
-Personality section is too short and also lacking. "Normal and gets well along with some people" feels like a cardboard cutout than an interesting character.
-Having to read a wiki article and still not understand a third of the words you've used in the profile is bad. Assume that the Permission Giver reading your request (and the people reading your spinoff) don't know an awful lot about the canon at hand.
-Having your agent actually affect the canon (and not come from a fanfic) makes him a bit too Suvian for comfort.

I think you're doing this wrong, and I think I have an exercise that can help you: instead of making an agent from Terraria, try — as an exercise, you don't have to use the resultant character in anything — to make an agent from World One, who arrived in the PPC via a generic plothole. I think this will force you to think about what makes them an interesting character instead of their powers or canon of origin or whatnot.