Storm King vs Gunmar

The wannabe conqueror of Equestria goes up against the tyrannical king of the Gumm-Gumms. Who wins and who dies?

Quotes:

Storm King: Here's the deal. I'm in the middle of a big re-brand here. "The Storm King" is tracking, well, as "intensely intimidating", but you know what? I need to back it up. You know what I need to back it up with? A storm! That would be greaaaat. 

Gunmar: They thought Killahead could stop me. This cage has only hardened me. When I bring forth the Eternal Night, Trolls will reclaim the surfacelands and take what’s rightfully ours.


Here are their strengths and weaknesses:

Storm King:
Strengths: Commands legions of yeti-like monsters called Storm Guards and possesses an artifact called the Staff of Sacanas which, when powered by the magic of all four alicorns, grants him the powers of a god. 
Weaknesses: Kind of an egotistical goofball and the staff only works with the magic of all the alicorns otherwise it's just a fancy looking stick with a jewel on it. 

Gunmar:
Strengths: Incredibly powerful, excellent fighter both hand to hand or armed, carries the Decimaar Blade which allows him dark magic at all times, can be summoned on a whim, and corrupt and turn other beings into monstrous Trolls called Gumm-Gumms which he has full control over and he can just replenish his forces even when his army's number dwindles. 
Weaknesses: Like all Trolls, Gunmar cannot step out into sunlight as it turns his skin into solid stone and can be instantly killed in this state via shattering. While he does show intelligence similar to that of a four-star strategist, his main style of fighting is more akin to a barbarian and his temper tends to blind him in combat.