First off, I might note that Fenrir is one my favorites when it comes to Norse Mythology. Though that is no excuse for what I'm about to say, it is an explanation.
The faceclaim is terrible, given that the web is full of better images. You could at least hide under a Spoiler tag, given that you clearly know how to use them.
One of his names being the father of werewolves doesn't make a lick of sense given that Fenrir was a wolf in the mythos, period. The werewolf legend is also more commonly associated with Southern Europe and the areas surrounding it, so I don't see what any of this has to do with Fenrir. Though as noted below, there were some Germanic werewolf legends.
Parameter-wise, I have no clue what you were going for here. EX Endurance is especially questionable, given that Fenrir got killed by Vidarr in Ragnarök and eaten by Surtr in a Lostbelt (though the latter was a world-burning monstrosity).
The background has nothing to do with Fenrir's. I would suggest finding some other character that fits into the idea you had even slightly.
Everything relating to the atrocious background in the Skills section is just as bad as the lore. Especially notable is that Odin liked Fenrir, so cursing him would be kinda odd. Wouldn't be the oddest thing the Allfather ever did, but still.
Why exactly does he have Self-Modification? I would assume some internal logic in the sheet, but aren't all the modifications dealing with him the work of someone else?
Instinct's rank is waaay too high. I get why you think he should have it (a beast's instinct or something like that), but Animalistic Logic is far more appropriate for someone who's, you know, a beast.
Why would a creature destined to aid in destroying the world (at least outside the fanfic of a background) have the blessing of Gaia? Also feels kinda uninspired. Too frolicky.
I believe I've mentioned my opinion on sticking to languages actually related to the subject of the sheet when it comes to Noble Phantasm names. Or who knows, maybe even one language per Noble Phantasm name?
Gleipnir is actually Norse, though its effect has nothing to do with the mythos (so at least its consistent with the rest of the sheet). Given that its supposed to be something binding Fenrir even in this atrocity of a sheet, I'd say it's remarkably bad at binding him. I would also suggest changing it from Anti-Bestiality to something else, given what that thing means. Or hey, maybe that's what it was really for.
TheraintropiaTherianthropia Markesh has (apparently) Greek and Hindi in its name. Like Self-Modification, there's no real reason for this to be here. Even if Fenris was some sorta werewolf (which, once again, is more a Greek-related concept, at least at the era we're talking about - there were some werewolf legends with Germanic roots, but they don't relate to Fenrir), he'd probably get beaten to the punch by Lycaon and the Neuri tribe.
Lunar Ecliptis has English and Dog Latin (which I guess is fitting in a way) in its name. As for its effect, whaddaya know, something that sorta relates to the mythology. As it happens, Fenrir did have children, though apparently actually named characters don't factor into this sheet. Said named children (Sköll and Hati) did actually have connections to the Sun and Moon, though in fairness they were mostly chasing them. Unless this has something to do with them somehow gaining the celestial bodies' powers after eating them during Ragnarök, I don't see why they'd have powers relating to them too. What makes even less sense is Fenrir being able to wield said powers at anything more than a minor level. There's also the fact that this Fenrir (even if his height doubles) is absurdly tiny. This NP is also the only part in the entire sheet that mentions Fenrir's Nasuverse canon ice powers.
And furthermore, please try to spell things correctly. At least for me the forum actively tries to warn me if it thinks I'm spelling something incorrectly, so...
Final rating, the sheet is an atrocity. Given that some of your prior works showed some promise, this is quite the step down.