could he in theory go macro?

DANG this is some quality content A+

Love the way he fills out, very soft and smooth looking. Out of curiosity, does he enjoy this sort of thing?

Awww thank you!
Personality wise, he can be an anxious guy, socially at least [he's quiet and calm but he can get to feeling awkward real easy and would rather duck out before confrontation ever occurs.]
So when it comes to this sort of thing, he would feel embarrassed, but if the situation were approached slowly and in a positive and gentle way (like bonding with someone)
That being said the way his body is constructed, this isn't hurting him (maybe the largest size is starting to get uncomfortable but he isn't being damaged.) so its mostly getting over the embarrassment and oddity factors.

So if it were approached the right way he could possibly be moved into a session of puffyness, but he'd likely always be a bit bashful about it. But a little reassuring goes a long way with him. :)

Oh gosh, he sounds like a total sweetheart! If you don't mind another question, I'm curious to know what fuels him. Does he get fuel by eating normal food, or does he refuel by consuming stuff like coal or oil? I hope you don't mind me asking; this is just a super interesting character!

I don't mind at all! It makes me happy when people are interested and like my characters c:

Since he runs on steam, his system is made to be quite efficient in turning what he consumes into vapor. He can actually consume normal food and drink though! He doesn't need too much to sustain him, but drinking clean water is best on his mechanical system while light meals are good for his organic body. He can break food down fairly efficiently (what cant be converted into anything useful is broken down into ash and dust, which is expelled just like the steam. Normally its minimal unless for some reason he's been forced to eat a lot of unhealthy things that his system can't break into anything useful at all. Then it'd be like expelling smog through his vents and coughing up noxious fumes until its all cleared away.)

So all in all he does need substance, food and water to keep going, but not a whole lot all at once to sustain him. Though technically he COULD consume a lot at once, but it'd break down and be converted fairly slowly. His system is efficient at the cost of time, which can be a double edged sword depending on what's been put into it. c:

It really looks like you've put a lot of thought into this guy! That brings up another question; if he were to eat more than he needed to sustain himself, would he gain weight, or would the excess food simply be held in his system until he needed to digest it? Like a car holding gasoline in the tank until it actually needs to consume that fuel.

He can actually gain weight yes!
Foods with heavy lipids or just overeating in general will actually add to organic growth like fats and the like because it'll try to feed his muscles/bio body too. What'd happen likely is because the eystem needs time to break things down, it'd sit for a bit in his stomach but would break down into either liquid or broken apart form because it'd just be uncomfortable and harder to move around (his species were designed to be good workers for their "boss"/designer) and it'd be troublesome if they weren't able to work for a day after mealtime xD
The organic fats and such will break down quickly/be burnt up quickly though if he were to start starving though. The body will go through its substances first but if those were completely empty, it'd start to burn up reserves and eventually if pushed past that point, possibly burn itself out. Luckily water is a "fuel" source as well, though it'll go quickly. But better than a system collapse!

He sounds like a really well-thought-out character! You've done a great job with this guy, and I can tell you've put a lot of time and thought into him. Thank you very much for taking time to answer my questions, I hope we'll get to see more of Vechar soon!

I had another question about Vechar, if it's alright to ask. I was wondering if he likes hugs, because he definitely looks quite soft and huggable, though you did say he's shy. Does he enjoy hugs, or is that something that'd make him feel awkward?

I hope I'm not being a bother with all these questions, I'm just genuinely curious, because this is a really unique, intriguing character concept!

Oh goodness its never a bother! It actually makes me really happy when someone likes one of my characters enough to want to learn about them!
He'd probably be really shy, but as long as someone asked first he'd be alright with it! c:

Ah, just noticed ya already answered this question on the other image. My bad ^^;