One main thing to know about Nik, don't ask him about his prosthesis (Unless if it's about how cool it is) nor his needed leg brace. It seems to be a subject he's rather sensitive about and doesn't want to talk about it. It does seem to have been something that affected him a long time ago now though, he seems to be able to work out and deal with the pain from his leg, and he doesn't seem to struggle with his one arm that badly when the prosthesis isn't in affect. The magic that creates this prosthesis is unknown, and seems to also be connected into Nik's life force, especially considering that it's the same tone that appears in his eyes - even Eggman has been unable to get this information out of him, much to the mans dismay, knowing that this must be some kind of very strong power source.

Eggman

Nik started working for the man after literally crashing sideways into the mans lab one day. After they all recovered from the shock of this, Nik started to let himself have a tour around Dr Eggman's lab. Rambling with Orbot & Cubot as he went, getting on the twos good sides with compliments on their mechanisms, Eggman followed him around complaining until Nik showed off his prosthesis. He did this to actually catch one of Dr Eggman's machines that Orbot managed to knock over, both catching the machine & the magic it has revealed; though he was slightly dismayed at the term magic rather then science. From there Nik begged to let him work with him, that he'd do it for no pay and no complaints as long as he was also given a chair at least to sleep on. Dr Eggman of course accepted, both out of curiosity and the fact he could never turn down some free labor, especially slightly more compitant labor.

The 'Gang'

It took about a week for Nik to meet any of Sonic's friends, heading out to go and collect one of Dr Eggman's lost machines, where he stumbled into Knuckles & Sticks. Nik is incredibly curious, he'd heard about Sonic and his gang, of course he had, and Dr Eggman was always complaining about how annoying they were, and the fact they were hanging off of one of their machines, he got it. Nik tried the friendly approach at first, to which Sticks almost immediately declared him as cursed which annoyed him terribly - Knuckles however, was just curious about the new face after the robot.
It took a bit of convincing, but Nik finally managed to get away with the machine, mostly intact, though Knuckles had left one mightly dent on the side of it. It's not until his fourth or fifth interaction with Knuckles that he spills who he works with. Though he tells the gang to not hold it personally, if he'd crashed into Tails' place he'd probably be aligned with them, he's just clung to the first thing he found here on this strange island.

• He may be a bat, and able to fly, but he is afraid of heights. He'll often tie his wings shut as to not have to fly.
• Prosthesis is optional & magic based, when active it is just like his other arm, and has sensation, but having it active is very draining to him and makes him sleepy.
• It's rarely seen without it's yellow scarf, it's unknown exactly why it's so important to them.
• Wears a brace / support tube up one leg to deal with a bad knee.
• He's not necessarily evil, yes he's an antagonist & works with someone who labels themselves as evil, but he views it as less black and white then that.
• Not the best at making anything robotic, but he likes fiddling with them and even spending time with them.
• Thinks that laws are too strict, what's a bit of evil lazers between two groups of people who'll never truly destroy each other.
• Does not see Knuckles as a little brother, fight him.
• Nik has had a couple of different dimensional adventures, with Ivan who crashed into their dimension, and he's fallen into a couple of others throughout his lifetime. Most times he's gone home a few minutes later, but he has spent longer in a few.