[@Jbcool] 
When I started creating the character, I had these concepts in mind dragon/fire breathing/sentient
[b]Dragon[/b] - hence the appearance you see and I added metal to look cool... also to enhance their weakness to heat, being a superconductor.
[b]Fire breathing[/b] -  I started reading about stars a lot so I went with the power coming from the process of fusion which also serves as his weakness
[b]Sentient[/b] - the most interesting story that came to mind was a kingdom of dragons, not boring democracy. A kingdom with unhappy citizens which led to a rebellion. The rebels were a group of terrorists, as seen by all, but most members believed in the cause. The leaders though were real terrorists, unhappy with the governing body and instead of wanting change they just wanted the ones on charge to suffer. The planet was already in danger of being destroyed and on the day where everyone was supposed to evacuate it, they sabotaged all the ships, trapping everyone on the planet. A war commenced lasting for weeks, the time still to little to repair the damage so everyone ended up dying. Everyone expect the ones I mentioned that did so by other means. I found this story very interesting so I incorporated it.

Yes, so I built this character on the assumption that I would take the role of a leader. So my character will not be working with you but your characters will be working for him. While travelling as a claw for hire he was paying and hiring crew people himself. They were given missions, missions of searching for the individuals he mentioned, to search for people who know the individuals he wants and so on. Fits the whole why be a mercenary thing. He is still in the lead unless someone has already taken the role. 

And why come there? Maybe he heard of someone who knows someone who knows about the dragon princess. He has been following ghost trails ever since he left his planet. Better than nothing. And this searching for someone excuse fits with [b]ANY [/b]story. 

Secondly, he was part of a force who dealt with these dangerous don't-wanna-die dragons and by "dealt" I mean face head first. Even in battle he was in the front line so I don't know where you got the ninja vibe. He is too big to be one, too heavy and his metal armor would suggest some affinity to combat on the battlefield like any armored warrior.

While true that the metal armor seems like over kill, but let me ask you this, does everyone fight with swords? I believe that at least [b]a few[/b] people use energy weapons and the sort. Energy=heat. So even if the hit doesn't physically harm him, it raises his temperature, causes him to inject more cooler substance on his organism. And that's another thing, the cooling system on his body. Even if his body is made of strong metal, place a few well aimed shots at the system, damage it so it can't be used, a few more shots on his body and see him overheat. Maybe I should've written this somewhere, thought I did, but the reason the ones who refused to die were hunted down was because at the end of their life cycle, once there was nothing more inside of them to power the fusion, they would violently explode, damaging all near them. Staying in hot places for too long sped up the process, in other terms sped the aging. The cooling system is all that freezes his "aging". So take out the cooling system, put a some well placed shots with a powerful energy/laser blaster and see him explode.

And the tail being a blowtorch...
I ask you, which is more effective, a strong deep quick knife stab, or standing close to the enemy with a blowtorch in hand keeping it in their skin and wait until it has lethal effect. It is mostly used to cut metal structures/doors. And as I said, it uses the power of his inner fusion. Overheating= stronger power, not overheating weak power. Also Overheating= close to kaboom.

Is that everything?