Firstly; To explain his seemingly total mastery of lighting; He has no other magical skills, Its lightning or nothing, He grew up in a household where demonic blood was the norm, so he grew up surounded by latent magic. He was the only one to manifest it so he was outcast, which means that he spent most of his time ostricised and thus doing the only thing he enjoyed, swordfighting and magic. He found he had a talent for lightning, so eschewed all others for that. Also, he's a Tiefling, so he allready has a good amount of latent power. Considering that he is the only true Non-human (with the exception of the weird resurrected guy). you'd expect him to be strong. Also, he's still young, if you notice he uses his powers with relative abandon and utter disregard for what they actually are. its doubtful he actually has any skill, rather just he has a immense range of random things he came up with, Also if you notice all the skills I mentioned are offencive, that's because magic wise his defences are rather low, The closest he's got is using St elmo's fire to deflect or absorb, and even then its rather hit and miss. 
Lets not go in to OP, Your char seems to (as you have stated) be able to beat anyone, also while he is a magic user you also implied he can nullify any magic at will. along with the fact 'enchanter' is a very open ended speciality. ranging from 'enchanting' objects to hold magical power, to using magical power to manipulate the world around them. And thats not to mention the fact he's basicly a ranger, (close, and long range combat, with magic on top) which means he probably is able to dual weild weapons. The list goes on. 

Please avoid threatening to kill other PC's Its rather childish. if you wish to do that I can play that game to; St elmo's fire disapates? Railgun, nothing left but a pair of smoking boots. Unavoidable, insta kill from throwing axe range! See! I can threaten to kill poeple to! lets all act like spoiled brats. that'll make this RP so much better. Honest it will. people bitching and bawling like 4 year olds always fixes things! 

Likelyhood of Alexander and Alej getting in a fight; 20%, since Alexander is more likely just to laugh at Alej and tell him to find something better to do than criticize others. 
Likelyhood of the fight turning lethal; 10% Alexander, being young, is very capacious, so is most likely just to dance round Alej and piss him off. 
Likelyhood of either of them winning; 1% Alexander, again is more likely to go "fuck I'm board" and just phase step out of there. probably leaving a eye of the storm behind as a joke. 
So is there even a real reason to argue this?

He's a Op char given the right personality, IE a destructive agressive one, or a vain proud one. But he dosn't have that, He's light hearted, capricious, chaotic and generally the sort who's "who gives a dam?" to most things, He's that kid in class with the amazing brain, but just can't be asked to do any of the questions. Ya know? the kid who never turns up but seems to do well in all the tests. You ever heard the term Virtuoso? Yeah, that's a good one to describe him, a Lazy Virtuoso.